Merge pull request #214 from Smithay/feature/nvidia

Add support for nvidia's EGLStream API

.github/workflows/ci.yml

@@ -19,6 +19,7 @@ jobs:
         - backend_drm
         - backend_drm_legacy
         - backend_drm_gbm
+        - backend_drm_eglstream
         - backend_drm_egl
         - backend_libinput
         - backend_udev

Cargo.toml

@@ -45,12 +45,13 @@ slog-term = "2.3"
 gl_generator = { version = "0.14", optional = true }
 
 [features]
-default = ["backend_winit", "backend_drm_legacy", "backend_drm_atomic", "backend_drm_gbm", "backend_drm_egl", "backend_libinput", "backend_udev", "backend_session_logind", "renderer_glium", "xwayland", "wayland_frontend"]
+default = ["backend_winit", "backend_drm_legacy", "backend_drm_atomic", "backend_drm_gbm", "backend_drm_eglstream", "backend_drm_egl", "backend_libinput", "backend_udev", "backend_session_logind", "renderer_glium", "xwayland", "wayland_frontend"]
 backend_winit = ["winit", "wayland-server/dlopen", "backend_egl", "wayland-egl", "renderer_gl", "use_system_lib"]
 backend_drm = ["drm", "failure"]
 backend_drm_atomic = ["backend_drm"]
 backend_drm_legacy = ["backend_drm"]
 backend_drm_gbm = ["backend_drm", "gbm", "image"]
+backend_drm_eglstream = ["backend_drm", "backend_egl"]
 backend_drm_egl = ["backend_drm", "backend_egl"]
 backend_egl = ["gl_generator"]
 backend_libinput = ["input"]

anvil/Cargo.toml

@@ -29,5 +29,5 @@ gl_generator = "0.14"
 default = [ "winit", "egl", "udev", "logind" ]
 egl = [ "smithay/use_system_lib" ]
 winit = [ "smithay/backend_winit" ]
-udev = [ "smithay/backend_libinput", "smithay/backend_udev", "smithay/backend_drm_atomic", "smithay/backend_drm_legacy", "smithay/backend_drm_gbm", "smithay/backend_drm_egl", "smithay/backend_session", "input" ]
+udev = [ "smithay/backend_libinput", "smithay/backend_udev", "smithay/backend_drm_atomic", "smithay/backend_drm_legacy", "smithay/backend_drm_gbm", "smithay/backend_drm_eglstream", "smithay/backend_drm_egl", "smithay/backend_session", "input" ]
 logind = [ "smithay/backend_session_logind" ]

anvil/src/udev.rs

@@ -18,9 +18,10 @@ use smithay::{
     backend::{
         drm::{
             atomic::AtomicDrmDevice,
-            common::fallback::FallbackDevice,
+            common::fallback::{FallbackDevice, FallbackSurface},
             device_bind,
             egl::{EglDevice, EglSurface},
+            eglstream::{egl::EglStreamDeviceBackend, EglStreamDevice, EglStreamSurface},
             gbm::{egl::Gbm as EglGbmBackend, GbmDevice, GbmSurface},
             legacy::LegacyDrmDevice,
             DevPath, Device, DeviceHandler, Surface,
@@ -76,12 +77,20 @@ impl AsRawFd for SessionFd {
     }
 }
 
-type RenderDevice = EglDevice<
+type RenderDevice = FallbackDevice<
-    EglGbmBackend<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>,
+    EglDevice<
-    GbmDevice<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>,
+        EglGbmBackend<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>,
+        GbmDevice<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>,
+    >,
+    EglDevice<
+        EglStreamDeviceBackend<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>,
+        EglStreamDevice<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>,
+    >,
+>;
+type RenderSurface = FallbackSurface<
+    EglSurface<GbmSurface<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>>,
+    EglSurface<EglStreamSurface<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>>,
 >;
-type RenderSurface =
-    EglSurface<GbmSurface<FallbackDevice<AtomicDrmDevice<SessionFd>, LegacyDrmDevice<SessionFd>>>>;
 
 pub fn run_udev(
     display: Rc<RefCell<Display>>,
@@ -301,7 +310,7 @@ impl<S: SessionNotifier, Data: 'static> UdevHandlerImpl<S, Data> {
                 .filter_map(|e| *e)
                 .flat_map(|encoder_handle| device.get_encoder_info(encoder_handle))
                 .collect::<Vec<EncoderInfo>>();
-            for encoder_info in encoder_infos {
+            'outer: for encoder_info in encoder_infos {
                 for crtc in res_handles.filter_crtcs(encoder_info.possible_crtcs()) {
                     if let Entry::Vacant(entry) = backends.entry(crtc) {
                         let renderer = GliumDrawer::init(
@@ -313,7 +322,7 @@ impl<S: SessionNotifier, Data: 'static> UdevHandlerImpl<S, Data> {
                         );
 
                         entry.insert(Rc::new(renderer));
-                        break;
+                        break 'outer;
                     }
                 }
             }
@@ -349,14 +358,14 @@ impl<S: SessionNotifier, Data: 'static> UdevHandlerImpl<S, Data> {
                 .filter_map(|e| *e)
                 .flat_map(|encoder_handle| device.get_encoder_info(encoder_handle))
                 .collect::<Vec<EncoderInfo>>();
-            for encoder_info in encoder_infos {
+            'outer: for encoder_info in encoder_infos {
                 for crtc in res_handles.filter_crtcs(encoder_info.possible_crtcs()) {
                     if !backends.contains_key(&crtc) {
                         let renderer =
                             GliumDrawer::init(device.create_surface(crtc).unwrap(), logger.clone());
 
                         backends.insert(crtc, Rc::new(renderer));
-                        break;
+                        break 'outer;
                     }
                 }
             }
@@ -376,23 +385,29 @@ impl<S: SessionNotifier, Data: 'static> UdevHandlerImpl<S, Data> {
                 OFlag::O_RDWR | OFlag::O_CLOEXEC | OFlag::O_NOCTTY | OFlag::O_NONBLOCK,
             )
             .ok()
-            .and_then(
+            .and_then(|fd| {
-                |fd| match FallbackDevice::new(SessionFd(fd), true, self.logger.clone()) {
+                match FallbackDevice::<AtomicDrmDevice<_>, LegacyDrmDevice<_>>::new(
+                    SessionFd(fd),
+                    true,
+                    self.logger.clone(),
+                ) {
                     Ok(drm) => Some(drm),
                     Err(err) => {
                         warn!(self.logger, "Skipping drm device, because of error: {}", err);
                         None
                     }
-                },
-            )
-            .and_then(|drm| match GbmDevice::new(drm, self.logger.clone()) {
-                Ok(gbm) => Some(gbm),
-                Err(err) => {
-                    warn!(self.logger, "Skipping gbm device, because of error: {}", err);
-                    None
                 }
             })
-            .and_then(|gbm| match EglDevice::new(gbm, self.logger.clone()) {
+            .and_then(|drm| {
+                match FallbackDevice::<GbmDevice<_>, EglStreamDevice<_>>::new(drm, self.logger.clone()) {
+                    Ok(dev) => Some(dev),
+                    Err(err) => {
+                        warn!(self.logger, "Skipping device, because of error: {}", err);
+                        None
+                    }
+                }
+            })
+            .and_then(|dev| match FallbackDevice::new_egl(dev, self.logger.clone()) {
                 Ok(egl) => Some(egl),
                 Err(err) => {
                     warn!(self.logger, "Skipping egl device, because of error: {}", err);
@@ -657,6 +672,7 @@ impl DrmRenderer {
                 };
 
                 if reschedule {
+                    debug!(self.logger, "Rescheduling");
                     match (timer, evt_handle) {
                         (Some(handle), _) => {
                             let _ = handle.add_timeout(

build.rs

@@ -32,6 +32,17 @@ fn main() {
                 "EGL_EXT_platform_wayland",
                 "EGL_EXT_platform_device",
                 "EGL_KHR_image_base",
+                "EGL_EXT_output_base",
+                "EGL_EXT_output_drm",
+                "EGL_EXT_device_drm",
+                "EGL_EXT_device_enumeration",
+                "EGL_EXT_device_query",
+                "EGL_KHR_stream",
+                "EGL_KHR_stream_producer_eglsurface",
+                "EGL_EXT_stream_consumer_egloutput",
+                "EGL_KHR_stream_fifo",
+                "EGL_NV_output_drm_flip_event",
+                "EGL_NV_stream_attrib",
             ],
         )
         .write_bindings(gl_generator::GlobalGenerator, &mut file)

examples/raw_nvidia.rs

@@ -0,0 +1,175 @@
+#![warn(rust_2018_idioms)]
+
+#[macro_use]
+extern crate slog;
+
+use glium::Surface as GliumSurface;
+use slog::Drain;
+use smithay::{
+    backend::{
+        drm::{
+            atomic::AtomicDrmDevice,
+            common::fallback::{EitherError, FallbackDevice},
+            common::Error as DrmError,
+            device_bind,
+            egl::{EglDevice, EglSurface, Error as EglError},
+            eglstream::{
+                egl::EglStreamDeviceBackend, EglStreamDevice, EglStreamSurface, Error as EglStreamError,
+            },
+            legacy::LegacyDrmDevice,
+            Device, DeviceHandler,
+        },
+        graphics::glium::GliumGraphicsBackend,
+    },
+    reexports::{
+        calloop::EventLoop,
+        drm::control::{connector::State as ConnectorState, crtc},
+    },
+};
+use std::{
+    fs::{File, OpenOptions},
+    io::Error as IoError,
+    os::unix::io::{AsRawFd, RawFd},
+    rc::Rc,
+    sync::Mutex,
+};
+
+pub struct ClonableFile {
+    file: File,
+}
+
+impl AsRawFd for ClonableFile {
+    fn as_raw_fd(&self) -> RawFd {
+        self.file.as_raw_fd()
+    }
+}
+
+impl Clone for ClonableFile {
+    fn clone(&self) -> Self {
+        ClonableFile {
+            file: self.file.try_clone().expect("Unable to clone file"),
+        }
+    }
+}
+
+fn main() {
+    let log = slog::Logger::root(Mutex::new(slog_term::term_full().fuse()).fuse(), o!());
+
+    /*
+     * Initialize the drm backend
+     */
+
+    // "Find" a suitable drm device
+    let mut options = OpenOptions::new();
+    options.read(true);
+    options.write(true);
+    let file = ClonableFile {
+        file: options.open("/dev/dri/card1").expect("Failed to open card1"),
+    };
+    let mut device = EglDevice::new(
+        EglStreamDevice::new(
+            FallbackDevice::<AtomicDrmDevice<_>, LegacyDrmDevice<_>>::new(file, true, log.clone())
+                .expect("Failed to initialize drm device"),
+            log.clone(),
+        )
+        .expect("Failed to initialize egl stream device"),
+        log.clone(),
+    )
+    .expect("Failed to initialize egl device");
+
+    // Get a set of all modesetting resource handles (excluding planes):
+    let res_handles = Device::resource_handles(&device).unwrap();
+
+    // Use first connected connector
+    let connector_info = res_handles
+        .connectors()
+        .iter()
+        .map(|conn| Device::get_connector_info(&device, *conn).unwrap())
+        .find(|conn| conn.state() == ConnectorState::Connected)
+        .unwrap();
+    println!("Conn: {:?}", connector_info.interface());
+
+    // Use the first encoder
+    let encoder_info =
+        Device::get_encoder_info(&device, connector_info.encoders()[0].expect("expected encoder")).unwrap();
+
+    // use the connected crtc if any
+    let crtc = encoder_info
+        .crtc()
+        // or use the first one that is compatible with the encoder
+        .unwrap_or_else(|| {
+            *res_handles
+                .filter_crtcs(encoder_info.possible_crtcs())
+                .iter()
+                .next()
+                .unwrap()
+        });
+    println!("Crtc {:?}", crtc);
+
+    // Assuming we found a good connector and loaded the info into `connector_info`
+    let mode = connector_info.modes()[0]; // Use first mode (usually highest resolution, but in reality you should filter and sort and check and match with other connectors, if you use more then one.)
+    println!("Mode: {:?}", mode);
+
+    // Initialize the hardware backend
+    let surface = device
+        .create_surface(crtc, mode, &[connector_info.handle()])
+        .expect("Failed to create surface");
+
+    let backend: Rc<GliumGraphicsBackend<_>> = Rc::new(surface.into());
+    device.set_handler(DrmHandlerImpl {
+        surface: backend.clone(),
+    });
+
+    /*
+     * Register the DrmDevice on the EventLoop
+     */
+    let mut event_loop = EventLoop::<()>::new().unwrap();
+    let _source = device_bind(&event_loop.handle(), device)
+        .map_err(|err| -> IoError { err.into() })
+        .unwrap();
+
+    // Start rendering
+    {
+        if let Err(smithay::backend::graphics::SwapBuffersError::ContextLost(err)) = backend.draw().finish() {
+            println!("{}", err);
+            return;
+        };
+    }
+
+    // Run
+    event_loop.run(None, &mut (), |_| {}).unwrap();
+}
+
+pub struct DrmHandlerImpl {
+    surface: Rc<
+        GliumGraphicsBackend<
+            EglSurface<
+                EglStreamSurface<
+                    FallbackDevice<AtomicDrmDevice<ClonableFile>, LegacyDrmDevice<ClonableFile>>,
+                >,
+            >,
+        >,
+    >,
+}
+
+impl DeviceHandler for DrmHandlerImpl {
+    type Device = EglDevice<
+        EglStreamDeviceBackend<FallbackDevice<AtomicDrmDevice<ClonableFile>, LegacyDrmDevice<ClonableFile>>>,
+        EglStreamDevice<FallbackDevice<AtomicDrmDevice<ClonableFile>, LegacyDrmDevice<ClonableFile>>>,
+    >;
+
+    fn vblank(&mut self, _crtc: crtc::Handle) {
+        {
+            println!("Vblank");
+            let mut frame = self.surface.draw();
+            frame.clear(None, Some((0.8, 0.8, 0.9, 1.0)), false, Some(1.0), None);
+            if let Err(smithay::backend::graphics::SwapBuffersError::ContextLost(err)) = frame.finish() {
+                panic!("Failed to swap: {}", err);
+            }
+        }
+    }
+
+    fn error(&mut self, error: EglError<EglStreamError<EitherError<DrmError, DrmError>>>) {
+        panic!("{:?}", error);
+    }
+}

src/backend/drm/atomic/mod.rs

@@ -61,7 +61,7 @@ type Mapping = (
     HashMap<plane::Handle, HashMap<String, property::Handle>>,
 );
 
-struct Dev<A: AsRawFd + 'static> {
+pub(in crate::backend::drm) struct Dev<A: AsRawFd + 'static> {
     fd: A,
     privileged: bool,
     active: Arc<AtomicBool>,

src/backend/drm/atomic/surface.rs

@@ -38,11 +38,11 @@ pub struct Planes {
     pub cursor: plane::Handle,
 }
 
-pub(super) struct AtomicDrmSurfaceInternal<A: AsRawFd + 'static> {
+pub(in crate::backend::drm) struct AtomicDrmSurfaceInternal<A: AsRawFd + 'static> {
     pub(super) dev: Rc<Dev<A>>,
-    pub(super) crtc: crtc::Handle,
+    pub(in crate::backend::drm) crtc: crtc::Handle,
     pub(super) cursor: CursorState,
-    pub(super) planes: Planes,
+    pub(in crate::backend::drm) planes: Planes,
     pub(super) state: RwLock<State>,
     pub(super) pending: RwLock<State>,
     pub(super) logger: ::slog::Logger,
@@ -918,7 +918,7 @@ impl<A: AsRawFd + 'static> AtomicDrmSurfaceInternal<A> {
         ))
     }
 
-    pub(crate) fn clear_plane(&self, plane: plane::Handle) -> Result<(), Error> {
+    pub(super) fn clear_plane(&self, plane: plane::Handle) -> Result<(), Error> {
         let mut req = AtomicModeReq::new();
 
         req.add_property(
@@ -948,7 +948,9 @@ impl<A: AsRawFd + 'static> AtomicDrmSurfaceInternal<A> {
 }
 
 /// Open raw crtc utilizing atomic mode-setting
-pub struct AtomicDrmSurface<A: AsRawFd + 'static>(pub(super) Rc<AtomicDrmSurfaceInternal<A>>);
+pub struct AtomicDrmSurface<A: AsRawFd + 'static>(
+    pub(in crate::backend::drm) Rc<AtomicDrmSurfaceInternal<A>>,
+);
 
 impl<A: AsRawFd + 'static> AsRawFd for AtomicDrmSurface<A> {
     fn as_raw_fd(&self) -> RawFd {

src/backend/drm/common/fallback.rs

@@ -2,9 +2,20 @@
 //! Types to make fallback device initialization easier
 //!
 
+#[cfg(feature = "backend_drm_egl")]
+use crate::backend::drm::egl::{Arguments as EglDeviceArguments, EglDevice, Error as EglDeviceError};
 #[cfg(all(feature = "backend_drm_atomic", feature = "backend_drm_legacy"))]
 use crate::backend::drm::{atomic::AtomicDrmDevice, legacy::LegacyDrmDevice};
 use crate::backend::drm::{common::Error, Device, DeviceHandler, RawDevice, RawSurface, Surface};
+#[cfg(all(feature = "backend_drm_gbm", feature = "backend_drm_eglstream"))]
+use crate::backend::drm::{
+    eglstream::{EglStreamDevice, Error as EglStreamError},
+    gbm::{Error as GbmError, GbmDevice},
+};
+#[cfg(feature = "backend_drm_egl")]
+use crate::backend::egl::context::{GlAttributes, PixelFormatRequirements};
+#[cfg(feature = "backend_drm_egl")]
+use crate::backend::egl::native::{Backend, NativeDisplay, NativeSurface};
 use crate::backend::egl::Error as EGLError;
 #[cfg(feature = "use_system_lib")]
 use crate::backend::egl::{display::EGLBufferReader, EGLGraphicsBackend};
@@ -36,23 +47,25 @@ pub enum FallbackDevice<D1: Device + 'static, D2: Device + 'static> {
     Fallback(D2),
 }
 
-struct FallbackDeviceHandlerD1<E, C, S1, S2, D1, D2>(
+struct FallbackDeviceHandlerD1<E1, E2, C, S1, S2, D1, D2>(
     Box<dyn DeviceHandler<Device = FallbackDevice<D1, D2>> + 'static>,
 )
 where
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + 'static,
-    S2: Surface<Error = E, Connectors = C> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + 'static,
     D1: Device<Surface = S1> + 'static,
     D2: Device<Surface = S2> + 'static;
 
-impl<E, C, S1, S2, D1, D2> DeviceHandler for FallbackDeviceHandlerD1<E, C, S1, S2, D1, D2>
+impl<E1, E2, C, S1, S2, D1, D2> DeviceHandler for FallbackDeviceHandlerD1<E1, E2, C, S1, S2, D1, D2>
 where
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + 'static,
-    S2: Surface<Error = E, Connectors = C> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + 'static,
     D1: Device<Surface = S1> + 'static,
     D2: Device<Surface = S2> + 'static,
 {
@@ -61,28 +74,30 @@ where
     fn vblank(&mut self, crtc: crtc::Handle) {
         self.0.vblank(crtc)
     }
-    fn error(&mut self, error: E) {
+    fn error(&mut self, error: E1) {
-        self.0.error(error);
+        self.0.error(EitherError::Either(error));
     }
 }
 
-struct FallbackDeviceHandlerD2<E, C, S1, S2, D1, D2>(
+struct FallbackDeviceHandlerD2<E1, E2, C, S1, S2, D1, D2>(
     Box<dyn DeviceHandler<Device = FallbackDevice<D1, D2>> + 'static>,
 )
 where
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + 'static,
-    S2: Surface<Error = E, Connectors = C> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + 'static,
     D1: Device<Surface = S1> + 'static,
     D2: Device<Surface = S2> + 'static;
 
-impl<E, C, S1, S2, D1, D2> DeviceHandler for FallbackDeviceHandlerD2<E, C, S1, S2, D1, D2>
+impl<E1, E2, C, S1, S2, D1, D2> DeviceHandler for FallbackDeviceHandlerD2<E1, E2, C, S1, S2, D1, D2>
 where
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + 'static,
-    S2: Surface<Error = E, Connectors = C> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + 'static,
     D1: Device<Surface = S1> + 'static,
     D2: Device<Surface = S2> + 'static,
 {
@@ -91,8 +106,8 @@ where
     fn vblank(&mut self, crtc: crtc::Handle) {
         self.0.vblank(crtc)
     }
-    fn error(&mut self, error: E) {
+    fn error(&mut self, error: E2) {
-        self.0.error(error);
+        self.0.error(EitherError::Or(error));
     }
 }
 
@@ -147,9 +162,33 @@ pub enum FallbackSurface<S1: Surface, S2: Surface> {
     Fallback(S2),
 }
 
+/// Enum uniting two kinds of possible errors.
+#[derive(Debug, thiserror::Error)]
+pub enum EitherError<E1: std::error::Error + 'static, E2: std::error::Error + 'static> {
+    /// Either this error
+    #[error("{0}")]
+    Either(#[source] E1),
+    /// Or this error
+    #[error("{0}")]
+    Or(#[source] E2),
+}
+
+impl<E1, E2> Into<SwapBuffersError> for EitherError<E1, E2>
+where
+    E1: std::error::Error + Into<SwapBuffersError> + 'static,
+    E2: std::error::Error + Into<SwapBuffersError> + 'static,
+{
+    fn into(self) -> SwapBuffersError {
+        match self {
+            EitherError::Either(err) => err.into(),
+            EitherError::Or(err) => err.into(),
+        }
+    }
+}
+
 #[cfg(all(feature = "backend_drm_atomic", feature = "backend_drm_legacy"))]
 impl<A: AsRawFd + Clone + 'static> FallbackDevice<AtomicDrmDevice<A>, LegacyDrmDevice<A>> {
-    /// Try to initialize an [`AtomicDrmDevice`](::backend::drm:;atomic::AtomicDrmDevice)
+    /// Try to initialize an [`AtomicDrmDevice`](::backend::drm::atomic::AtomicDrmDevice)
     /// and fall back to a [`LegacyDrmDevice`] if atomic-modesetting is not supported.
     ///
     /// # Arguments
@@ -203,6 +242,146 @@ impl<A: AsRawFd + Clone + 'static> FallbackDevice<AtomicDrmDevice<A>, LegacyDrmD
     }
 }
 
+#[cfg(all(
+    feature = "backend_drm_gbm",
+    feature = "backend_drm_eglstream",
+    feature = "backend_udev"
+))]
+type GbmOrEglStreamError<D> = EitherError<
+    GbmError<<<D as Device>::Surface as Surface>::Error>,
+    EglStreamError<<<D as Device>::Surface as Surface>::Error>,
+>;
+#[cfg(all(
+    feature = "backend_drm_gbm",
+    feature = "backend_drm_eglstream",
+    feature = "backend_udev"
+))]
+impl<D> FallbackDevice<GbmDevice<D>, EglStreamDevice<D>>
+where
+    D: RawDevice + ControlDevice + 'static,
+{
+    /// Try to initialize a [`GbmDevice`](::backend::drm::gbm::GbmDevice)
+    /// or a [`EglStreamDevice`](::backend::drm::eglstream::EglStreamDevice) depending on the used driver.
+    ///
+    /// # Arguments
+    ///
+    /// - `dev` - Open drm device (needs implement [`RawDevice`](::backend::drm::RawDevice))
+    /// - `logger` - Optional [`slog::Logger`] to be used by the resulting device.
+    ///
+    /// # Return
+    ///
+    /// Returns an error, if the choosen device fails to initialize.
+    pub fn new<L>(dev: D, logger: L) -> Result<Self, GbmOrEglStreamError<D>>
+    where
+        L: Into<Option<::slog::Logger>>,
+    {
+        let log = crate::slog_or_stdlog(logger).new(o!("smithay_module" => "backend_drm_fallback"));
+
+        let driver = crate::backend::udev::driver(dev.device_id()).expect("Failed to query device");
+        info!(log, "Drm device driver: {:?}", driver);
+        if driver.as_ref().and_then(|x| x.to_str()) == Some("nvidia") {
+            Ok(FallbackDevice::Fallback(
+                EglStreamDevice::new(dev, log).map_err(EitherError::Or)?,
+            ))
+        } else {
+            Ok(FallbackDevice::Preference(
+                GbmDevice::new(dev, log.clone()).map_err(EitherError::Either)?,
+            ))
+        }
+    }
+}
+
+#[cfg(feature = "backend_drm_egl")]
+type EglUnderlying<D1, D2> = EitherError<
+    EglDeviceError<<<D1 as Device>::Surface as Surface>::Error>,
+    EglDeviceError<<<D2 as Device>::Surface as Surface>::Error>,
+>;
+
+#[cfg(feature = "backend_drm_egl")]
+type FallbackEglDevice<B1, D1, B2, D2> = FallbackDevice<EglDevice<B1, D1>, EglDevice<B2, D2>>;
+
+#[cfg(feature = "backend_drm_egl")]
+impl<D1, D2> FallbackDevice<D1, D2>
+where
+    D1: Device + 'static,
+    <D1 as Device>::Surface: NativeSurface<Error = <<D1 as Device>::Surface as Surface>::Error>,
+    D2: Device + 'static,
+    <D2 as Device>::Surface: NativeSurface<Error = <<D2 as Device>::Surface as Surface>::Error>,
+{
+    /// Try to create a new [`EglDevice`] from a [`FallbackDevice`] containing two compatible device types.
+    ///
+    /// This helper function is necessary as implementing [`NativeDevice`](::backend::egl::native::NativeDevice) for [`FallbackDevice`] is impossible
+    /// as selecting the appropriate [`Backend`](::backend::egl::native::Backend) would be impossible without knowing
+    /// the underlying device type, that was selected by [`FallbackDevice`].
+    ///
+    /// Returns an error if the context creation was not successful.
+    pub fn new_egl<B1, B2, L>(
+        dev: FallbackDevice<D1, D2>,
+        logger: L,
+    ) -> Result<FallbackEglDevice<B1, D1, B2, D2>, EglUnderlying<D1, D2>>
+    where
+        B1: Backend<Surface = <D1 as Device>::Surface, Error = <<D1 as Device>::Surface as Surface>::Error>
+            + 'static,
+        D1: NativeDisplay<B1, Arguments = EglDeviceArguments>,
+        B2: Backend<Surface = <D2 as Device>::Surface, Error = <<D2 as Device>::Surface as Surface>::Error>
+            + 'static,
+        D2: NativeDisplay<B2, Arguments = EglDeviceArguments>,
+        L: Into<Option<::slog::Logger>>,
+    {
+        let log = crate::slog_or_stdlog(logger).new(o!("smithay_module" => "backend_drm_fallback"));
+        match dev {
+            FallbackDevice::Preference(gbm) => match EglDevice::new(gbm, log) {
+                Ok(dev) => Ok(FallbackDevice::Preference(dev)),
+                Err(err) => Err(EglUnderlying::<D1, D2>::Either(err)),
+            },
+            FallbackDevice::Fallback(eglstream) => match EglDevice::new(eglstream, log) {
+                Ok(dev) => Ok(FallbackDevice::Fallback(dev)),
+                Err(err) => Err(EglUnderlying::<D1, D2>::Or(err)),
+            },
+        }
+    }
+
+    /// Try to create a new [`EglDevice`] from a [`FallbackDevice`] containing two compatible device types with
+    /// the given attributes and requirements as defaults for new surfaces.
+    ///
+    /// This helper function is necessary as implementing [`NativeDevice`](::backend::egl::native::NativeDevice) for [`FallbackDevice`] is impossible
+    /// as selecting the appropriate [`Backend`](::backend::egl::native::Backend) would be impossible without knowing
+    /// the underlying device type, that was selected by [`FallbackDevice`].
+    ///
+    /// Returns an error if the context creation was not successful.
+    pub fn new_egl_with_defaults<B1, B2, L>(
+        dev: FallbackDevice<D1, D2>,
+        default_attributes: GlAttributes,
+        default_requirements: PixelFormatRequirements,
+        logger: L,
+    ) -> Result<FallbackEglDevice<B1, D1, B2, D2>, EglUnderlying<D1, D2>>
+    where
+        B1: Backend<Surface = <D1 as Device>::Surface, Error = <<D1 as Device>::Surface as Surface>::Error>
+            + 'static,
+        D1: NativeDisplay<B1, Arguments = EglDeviceArguments>,
+        B2: Backend<Surface = <D2 as Device>::Surface, Error = <<D2 as Device>::Surface as Surface>::Error>
+            + 'static,
+        D2: NativeDisplay<B2, Arguments = EglDeviceArguments>,
+        L: Into<Option<::slog::Logger>>,
+    {
+        let log = crate::slog_or_stdlog(logger).new(o!("smithay_module" => "backend_drm_fallback"));
+        match dev {
+            FallbackDevice::Preference(gbm) => {
+                match EglDevice::new_with_defaults(gbm, default_attributes, default_requirements, log) {
+                    Ok(dev) => Ok(FallbackDevice::Preference(dev)),
+                    Err(err) => Err(EglUnderlying::<D1, D2>::Either(err)),
+                }
+            }
+            FallbackDevice::Fallback(eglstream) => {
+                match EglDevice::new_with_defaults(eglstream, default_attributes, default_requirements, log) {
+                    Ok(dev) => Ok(FallbackDevice::Fallback(dev)),
+                    Err(err) => Err(EglUnderlying::<D1, D2>::Or(err)),
+                }
+            }
+        }
+    }
+}
+
 macro_rules! fallback_device_impl {
     ($func_name:ident, $self:ty, $return:ty, $($arg_name:ident : $arg_ty:ty),*) => {
         fn $func_name(self: $self, $($arg_name : $arg_ty),*) -> $return {
@@ -219,6 +398,19 @@ macro_rules! fallback_device_impl {
         fallback_device_impl!($func_name, $self, ());
     };
 }
+macro_rules! fallback_device_err_impl {
+    ($func_name:ident, $self:ty, $return:ty, $($arg_name:ident : $arg_ty:ty),*) => {
+        fn $func_name(self: $self, $($arg_name : $arg_ty),*) -> $return {
+            match self {
+                FallbackDevice::Preference(dev) => dev.$func_name($($arg_name),*).map_err(EitherError::Either),
+                FallbackDevice::Fallback(dev) => dev.$func_name($($arg_name),*).map_err(EitherError::Or),
+            }
+        }
+    };
+    ($func_name:ident, $self:ty, $return:ty) => {
+        fallback_device_err_impl!($func_name, $self, $return,);
+    };
+}
 
 macro_rules! fallback_surface_impl {
     ($func_name:ident, $self:ty, $return:ty, $($arg_name:ident : $arg_ty:ty),*) => {
@@ -236,6 +428,16 @@ macro_rules! fallback_surface_impl {
         fallback_surface_impl!($func_name, $self, ());
     };
 }
+macro_rules! fallback_surface_err_impl {
+    ($func_name:ident, $self:ty, $return:ty, $($arg_name:ident : $arg_ty:ty),*) => {
+        fn $func_name(self: $self, $($arg_name : $arg_ty),*) -> $return {
+            match self {
+                FallbackSurface::Preference(dev) => dev.$func_name($($arg_name),*).map_err(EitherError::Either),
+                FallbackSurface::Fallback(dev) => dev.$func_name($($arg_name),*).map_err(EitherError::Or),
+            }
+        }
+    };
+}
 
 impl<D1: Device, D2: Device> AsRawFd for FallbackDevice<D1, D2> {
     fallback_device_impl!(as_raw_fd, &Self, RawFd);
@@ -243,13 +445,14 @@ impl<D1: Device, D2: Device> AsRawFd for FallbackDevice<D1, D2> {
 impl<D1: Device + BasicDevice, D2: Device + BasicDevice> BasicDevice for FallbackDevice<D1, D2> {}
 impl<D1: Device + ControlDevice, D2: Device + ControlDevice> ControlDevice for FallbackDevice<D1, D2> {}
 
-impl<E, C, S1, S2, D1, D2> Device for FallbackDevice<D1, D2>
+impl<E1, E2, C, S1, S2, D1, D2> Device for FallbackDevice<D1, D2>
 where
-    // Connectors and Error need to match for both Surfaces
+    // Connectors need to match for both Surfaces
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + 'static,
-    S2: Surface<Error = E, Connectors = C> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + 'static,
     D1: Device<Surface = S1> + 'static,
     D2: Device<Surface = S2> + 'static,
 {
@@ -268,18 +471,20 @@ where
         crtc: crtc::Handle,
         mode: Mode,
         connectors: &[connector::Handle],
-    ) -> Result<Self::Surface, E> {
+    ) -> Result<Self::Surface, EitherError<E1, E2>> {
         match self {
             FallbackDevice::Preference(dev) => Ok(FallbackSurface::Preference(
-                dev.create_surface(crtc, mode, connectors)?,
+                dev.create_surface(crtc, mode, connectors)
+                    .map_err(EitherError::Either)?,
             )),
             FallbackDevice::Fallback(dev) => Ok(FallbackSurface::Fallback(
-                dev.create_surface(crtc, mode, connectors)?,
+                dev.create_surface(crtc, mode, connectors)
+                    .map_err(EitherError::Or)?,
             )),
         }
     }
     fallback_device_impl!(process_events, &mut Self);
-    fallback_device_impl!(resource_handles, &Self, Result<ResourceHandles, E>);
+    fallback_device_err_impl!(resource_handles, &Self, Result<ResourceHandles, EitherError<E1, E2>>);
     fallback_device_impl!(get_connector_info, &Self, Result<connector::Info, DrmError>, conn: connector::Handle);
     fallback_device_impl!(get_crtc_info, &Self, Result<crtc::Info, DrmError>, crtc: crtc::Handle);
     fallback_device_impl!(get_encoder_info, &Self, Result<encoder::Info, DrmError>, enc: encoder::Handle);
@@ -288,13 +493,14 @@ where
 }
 
 // Impl RawDevice where underlying types implement RawDevice
-impl<E, C, S1, S2, D1, D2> RawDevice for FallbackDevice<D1, D2>
+impl<E1, E2, C, S1, S2, D1, D2> RawDevice for FallbackDevice<D1, D2>
 where
-    // Connectors and Error need to match for both Surfaces
+    // Connectors need to match for both Surfaces
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: RawSurface + Surface<Error = E, Connectors = C> + 'static,
+    S1: RawSurface + Surface<Error = E1, Connectors = C> + 'static,
-    S2: RawSurface + Surface<Error = E, Connectors = C> + 'static,
+    S2: RawSurface + Surface<Error = E2, Connectors = C> + 'static,
     D1: RawDevice<Surface = S1> + 'static,
     D2: RawDevice<Surface = S2> + 'static,
 {
@@ -308,41 +514,47 @@ impl<D1: Device + EGLGraphicsBackend + 'static, D2: Device + EGLGraphicsBackend
     fallback_device_impl!(bind_wl_display, &Self, Result<EGLBufferReader, EGLError>, display : &Display);
 }
 
-impl<E, C, S1, S2> Surface for FallbackSurface<S1, S2>
+impl<E1, E2, C, S1, S2> Surface for FallbackSurface<S1, S2>
 where
-    // Connectors and Error need to match for both Surfaces
+    // Connectors need to match for both Surfaces
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + 'static,
-    S2: Surface<Error = E, Connectors = C> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + 'static,
 {
-    type Error = E;
+    type Error = EitherError<E1, E2>;
     type Connectors = C;
 
     fallback_surface_impl!(crtc, &Self, crtc::Handle);
     fallback_surface_impl!(current_connectors, &Self, C);
     fallback_surface_impl!(pending_connectors, &Self, C);
-    fallback_surface_impl!(add_connector, &Self, Result<(), E>, conn: connector::Handle);
+    fallback_surface_err_impl!(add_connector, &Self, Result<(), EitherError<E1, E2>>, conn: connector::Handle);
-    fallback_surface_impl!(remove_connector, &Self, Result<(), E>, conn: connector::Handle);
+    fallback_surface_err_impl!(remove_connector, &Self, Result<(), EitherError<E1, E2>>, conn: connector::Handle);
-    fallback_surface_impl!(set_connectors, &Self, Result<(), E>, conns: &[connector::Handle]);
+    fallback_surface_err_impl!(set_connectors, &Self, Result<(), EitherError<E1, E2>>, conns: &[connector::Handle]);
     fallback_surface_impl!(current_mode, &Self, Mode);
     fallback_surface_impl!(pending_mode, &Self, Mode);
-    fallback_surface_impl!(use_mode, &Self, Result<(), E>, mode: Mode);
+    fallback_surface_err_impl!(use_mode, &Self, Result<(), EitherError<E1, E2>>, mode: Mode);
 }
 
-impl<E, C, S1, S2> RawSurface for FallbackSurface<S1, S2>
+impl<E1, E2, C, S1, S2> RawSurface for FallbackSurface<S1, S2>
 where
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: RawSurface + Surface<Error = E, Connectors = C> + 'static,
+    S1: RawSurface + Surface<Error = E1, Connectors = C> + 'static,
-    S2: RawSurface + Surface<Error = E, Connectors = C> + 'static,
+    S2: RawSurface + Surface<Error = E2, Connectors = C> + 'static,
 {
     fallback_surface_impl!(commit_pending, &Self, bool);
-    fallback_surface_impl!(commit, &Self, Result<(), E>, fb: framebuffer::Handle);
+    fallback_surface_err_impl!(commit, &Self, Result<(), EitherError<E1, E2>>, fb: framebuffer::Handle);
-    fn page_flip(&self, framebuffer: framebuffer::Handle) -> Result<(), E> {
+    fn page_flip(&self, framebuffer: framebuffer::Handle) -> Result<(), EitherError<E1, E2>> {
         match self {
-            FallbackSurface::Preference(dev) => RawSurface::page_flip(dev, framebuffer),
+            FallbackSurface::Preference(dev) => {
-            FallbackSurface::Fallback(dev) => RawSurface::page_flip(dev, framebuffer),
+                RawSurface::page_flip(dev, framebuffer).map_err(EitherError::Either)
+            }
+            FallbackSurface::Fallback(dev) => {
+                RawSurface::page_flip(dev, framebuffer).map_err(EitherError::Or)
+            }
         }
     }
 }
@@ -353,29 +565,32 @@ impl<S1: Surface + AsRawFd, S2: Surface + AsRawFd> AsRawFd for FallbackSurface<S
 impl<S1: Surface + BasicDevice, S2: Surface + BasicDevice> BasicDevice for FallbackSurface<S1, S2> {}
 impl<S1: Surface + ControlDevice, S2: Surface + ControlDevice> ControlDevice for FallbackSurface<S1, S2> {}
 
-impl<E1, E2, C, CF, S1, S2> CursorBackend for FallbackSurface<S1, S2>
+impl<E1, E2, E3, E4, C, CF, S1, S2> CursorBackend for FallbackSurface<S1, S2>
 where
     E1: std::error::Error + Send + 'static,
-    E2: 'static,
+    E2: std::error::Error + Send + 'static,
+    E3: std::error::Error + 'static,
+    E4: std::error::Error + 'static,
     CF: ?Sized,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E1, Connectors = C> + CursorBackend<CursorFormat = CF, Error = E2> + 'static,
+    S1: Surface<Error = E1, Connectors = C> + CursorBackend<CursorFormat = CF, Error = E3> + 'static,
-    S2: Surface<Error = E1, Connectors = C> + CursorBackend<CursorFormat = CF, Error = E2> + 'static,
+    S2: Surface<Error = E2, Connectors = C> + CursorBackend<CursorFormat = CF, Error = E4> + 'static,
 {
     type CursorFormat = CF;
-    type Error = E2;
+    type Error = EitherError<E3, E4>;
 
-    fallback_surface_impl!(set_cursor_position, &Self, Result<(), E2>, x: u32, y: u32);
+    fallback_surface_err_impl!(set_cursor_position, &Self, Result<(), EitherError<E3, E4>>, x: u32, y: u32);
-    fallback_surface_impl!(set_cursor_representation, &Self, Result<(), E2>, buffer: &Self::CursorFormat, hotspot: (u32, u32));
+    fallback_surface_err_impl!(set_cursor_representation, &Self, Result<(), EitherError<E3, E4>>, buffer: &Self::CursorFormat, hotspot: (u32, u32));
 }
 
 #[cfg(feature = "renderer_gl")]
-impl<E, C, S1, S2> GLGraphicsBackend for FallbackSurface<S1, S2>
+impl<E1, E2, C, S1, S2> GLGraphicsBackend for FallbackSurface<S1, S2>
 where
-    E: std::error::Error + Send + 'static,
+    E1: std::error::Error + Send + 'static,
+    E2: std::error::Error + Send + 'static,
     C: IntoIterator<Item = connector::Handle> + 'static,
-    S1: Surface<Error = E, Connectors = C> + GLGraphicsBackend + 'static,
+    S1: Surface<Error = E1, Connectors = C> + GLGraphicsBackend + 'static,
-    S2: Surface<Error = E, Connectors = C> + GLGraphicsBackend + 'static,
+    S2: Surface<Error = E2, Connectors = C> + GLGraphicsBackend + 'static,
 {
     fallback_surface_impl!(swap_buffers, &Self, Result<(), SwapBuffersError>);
     fallback_surface_impl!(get_proc_address, &Self, *const c_void, symbol: &str);

src/backend/drm/egl/mod.rs

@@ -46,17 +46,16 @@ pub enum Error<U: std::error::Error + std::fmt::Debug + std::fmt::Display + 'sta
     Underlying(#[source] U),
 }
 
-type Arguments = (crtc::Handle, Mode, Vec<connector::Handle>);
+pub(crate) type Arguments = (crtc::Handle, Mode, Vec<connector::Handle>);
 type BackendRef<D> = Weak<EglSurfaceInternal<<D as Device>::Surface>>;
 
 /// Representation of an egl device to create egl rendering surfaces
 pub struct EglDevice<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     dev: EGLDisplay<B, D>,
     logger: ::slog::Logger,
@@ -67,11 +66,10 @@ where
 
 impl<B, D> AsRawFd for EglDevice<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     fn as_raw_fd(&self) -> RawFd {
         self.dev.borrow().as_raw_fd()
@@ -80,11 +78,10 @@ where
 
 impl<B, D> EglDevice<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     /// Try to create a new [`EglDevice`] from an open device.
     ///
@@ -138,22 +135,20 @@ where
 
 struct InternalDeviceHandler<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     handler: Box<dyn DeviceHandler<Device = EglDevice<B, D>> + 'static>,
 }
 
 impl<B, D> DeviceHandler for InternalDeviceHandler<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     type Device = D;
 
@@ -167,11 +162,10 @@ where
 
 impl<B, D> Device for EglDevice<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     type Surface = EglSurface<<D as Device>::Surface>;
 
@@ -250,11 +244,10 @@ where
 #[cfg(feature = "use_system_lib")]
 impl<B, D> EGLGraphicsBackend for EglDevice<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     fn bind_wl_display(&self, display: &Display) -> Result<EGLBufferReader, EGLError> {
         self.dev.bind_wl_display(display)
@@ -263,11 +256,10 @@ where
 
 impl<B, D> Drop for EglDevice<B, D>
 where
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<B, Arguments = Arguments, Error = <<D as Device>::Surface as Surface>::Error>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device + NativeDisplay<B, Arguments = Arguments> + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     fn drop(&mut self) {
         self.clear_handler();

src/backend/drm/egl/session.rs

@@ -28,15 +28,13 @@ pub struct EglDeviceObserver<S: SessionObserver + 'static, N: NativeSurface + Su
 impl<S, B, D> AsSessionObserver<EglDeviceObserver<S, <D as Device>::Surface>> for EglDevice<B, D>
 where
     S: SessionObserver + 'static,
-    B: Backend<Surface = <D as Device>::Surface> + 'static,
+    B: Backend<Surface = <D as Device>::Surface, Error = <<D as Device>::Surface as Surface>::Error>
-    D: Device
-        + NativeDisplay<
-            B,
-            Arguments = (crtc::Handle, Mode, Vec<connector::Handle>),
-            Error = <<D as Device>::Surface as Surface>::Error,
-        > + AsSessionObserver<S>
         + 'static,
-    <D as Device>::Surface: NativeSurface,
+    D: Device
+        + NativeDisplay<B, Arguments = (crtc::Handle, Mode, Vec<connector::Handle>)>
+        + AsSessionObserver<S>
+        + 'static,
+    <D as Device>::Surface: NativeSurface<Error = <<D as Device>::Surface as Surface>::Error>,
 {
     fn observer(&mut self) -> EglDeviceObserver<S, <D as Device>::Surface> {
         EglDeviceObserver {

src/backend/drm/eglstream/egl.rs

@@ -0,0 +1,238 @@
+//!
+//! Egl [`NativeDisplay`](::backend::egl::native::NativeDisplay) and
+//! [`NativeSurface`](::backend::egl::native::NativeSurface) support for
+//! [`EglStreamDevice`](EglStreamDevice) and [`EglStreamSurface`](EglStreamSurface).
+//!
+
+#[cfg(feature = "backend_drm_atomic")]
+use crate::backend::drm::atomic::AtomicDrmDevice;
+#[cfg(all(feature = "backend_drm_atomic", feature = "backend_drm_legacy"))]
+use crate::backend::drm::common::fallback::{EitherError, FallbackDevice, FallbackSurface};
+#[cfg(any(feature = "backend_drm_atomic", feature = "backend_drm_legacy"))]
+use crate::backend::drm::common::Error as DrmError;
+#[cfg(feature = "backend_drm_legacy")]
+use crate::backend::drm::legacy::LegacyDrmDevice;
+use crate::backend::drm::{Device, RawDevice, RawSurface, Surface};
+use crate::backend::egl::native::{Backend, NativeDisplay, NativeSurface};
+use crate::backend::egl::{
+    display::EGLDisplayHandle, ffi, wrap_egl_call, EGLError, Error as EglBackendError, SurfaceCreationError,
+    SwapBuffersError,
+};
+
+use super::Error;
+use super::{EglStreamDevice, EglStreamSurface};
+
+use drm::control::{connector, crtc, Device as ControlDevice, Mode};
+use nix::libc::{c_int, c_void};
+use std::marker::PhantomData;
+use std::os::unix::io::AsRawFd;
+use std::sync::Arc;
+
+/// Egl Device backend type
+///
+/// See [`Backend`](::backend::egl::native::Backend).
+pub struct EglStreamDeviceBackend<D: RawDevice + 'static> {
+    _userdata: PhantomData<D>,
+}
+
+impl<D: RawDevice + 'static> Backend for EglStreamDeviceBackend<D>
+where
+    EglStreamSurface<D>: NativeSurface<Error = Error<<<D as Device>::Surface as Surface>::Error>>,
+{
+    type Surface = EglStreamSurface<D>;
+    type Error = Error<<<D as Device>::Surface as Surface>::Error>;
+
+    unsafe fn get_display<F>(
+        display: ffi::NativeDisplayType,
+        attribs: &[ffi::EGLint],
+        has_dp_extension: F,
+        log: ::slog::Logger,
+    ) -> Result<ffi::egl::types::EGLDisplay, EGLError>
+    where
+        F: Fn(&str) -> bool,
+    {
+        if has_dp_extension("EGL_EXT_platform_device") && ffi::egl::GetPlatformDisplayEXT::is_loaded() {
+            debug!(
+                log,
+                "EGL Display Initialization via EGL_EXT_platform_device with {:?}", display
+            );
+            wrap_egl_call(|| {
+                ffi::egl::GetPlatformDisplayEXT(
+                    ffi::egl::PLATFORM_DEVICE_EXT,
+                    display as *mut _,
+                    attribs.as_ptr() as *const _,
+                )
+            })
+        } else {
+            Ok(ffi::egl::NO_DISPLAY)
+        }
+    }
+}
+
+unsafe impl<D: RawDevice + ControlDevice + 'static> NativeDisplay<EglStreamDeviceBackend<D>>
+    for EglStreamDevice<D>
+where
+    EglStreamSurface<D>: NativeSurface<Error = Error<<<D as Device>::Surface as Surface>::Error>>,
+{
+    type Arguments = (crtc::Handle, Mode, Vec<connector::Handle>);
+
+    fn is_backend(&self) -> bool {
+        true
+    }
+
+    fn ptr(&self) -> Result<ffi::NativeDisplayType, EglBackendError> {
+        Ok(self.dev as *const _)
+    }
+
+    fn attributes(&self) -> Vec<ffi::EGLint> {
+        vec![
+            ffi::egl::DRM_MASTER_FD_EXT as ffi::EGLint,
+            self.raw.as_raw_fd(),
+            ffi::egl::NONE as i32,
+        ]
+    }
+
+    fn surface_type(&self) -> ffi::EGLint {
+        ffi::egl::STREAM_BIT_KHR as ffi::EGLint
+    }
+
+    fn create_surface(
+        &mut self,
+        args: Self::Arguments,
+    ) -> Result<EglStreamSurface<D>, Error<<<D as Device>::Surface as Surface>::Error>> {
+        Device::create_surface(self, args.0, args.1, &args.2)
+    }
+}
+
+#[cfg(feature = "backend_drm_atomic")]
+unsafe impl<A: AsRawFd + 'static> NativeSurface for EglStreamSurface<AtomicDrmDevice<A>> {
+    type Error = Error<DrmError>;
+
+    unsafe fn create(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attribs: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Self::Error>> {
+        let output_attributes = {
+            let mut out: Vec<isize> = Vec::with_capacity(3);
+            out.push(ffi::egl::DRM_PLANE_EXT as isize);
+            out.push(Into::<u32>::into(self.0.crtc.0.planes.primary) as isize);
+            out.push(ffi::egl::NONE as isize);
+            out
+        };
+
+        self.create_surface(display, config_id, surface_attribs, &output_attributes)
+            .map_err(SurfaceCreationError::NativeSurfaceCreationFailed)
+    }
+
+    fn needs_recreation(&self) -> bool {
+        self.0.crtc.commit_pending()
+    }
+
+    fn swap_buffers(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        surface: ffi::egl::types::EGLSurface,
+    ) -> Result<(), SwapBuffersError<Error<DrmError>>> {
+        if let Some((buffer, fb)) = self.0.commit_buffer.take() {
+            let _ = self.0.crtc.destroy_framebuffer(fb);
+            let _ = self.0.crtc.destroy_dumb_buffer(buffer);
+        }
+
+        self.flip(self.0.crtc.0.crtc, display, surface)
+    }
+}
+
+#[cfg(feature = "backend_drm_legacy")]
+unsafe impl<A: AsRawFd + 'static> NativeSurface for EglStreamSurface<LegacyDrmDevice<A>> {
+    type Error = Error<DrmError>;
+
+    unsafe fn create(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attribs: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Self::Error>> {
+        let output_attributes = {
+            let mut out: Vec<isize> = Vec::with_capacity(3);
+            out.push(ffi::egl::DRM_CRTC_EXT as isize);
+            out.push(Into::<u32>::into(self.0.crtc.0.crtc) as isize);
+            out.push(ffi::egl::NONE as isize);
+            out
+        };
+
+        self.create_surface(display, config_id, surface_attribs, &output_attributes)
+            .map_err(SurfaceCreationError::NativeSurfaceCreationFailed)
+    }
+
+    fn needs_recreation(&self) -> bool {
+        self.0.crtc.commit_pending()
+    }
+
+    fn swap_buffers(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        surface: ffi::egl::types::EGLSurface,
+    ) -> Result<(), SwapBuffersError<Error<DrmError>>> {
+        if let Some((buffer, fb)) = self.0.commit_buffer.take() {
+            let _ = self.0.crtc.destroy_framebuffer(fb);
+            let _ = self.0.crtc.destroy_dumb_buffer(buffer);
+        }
+        self.flip(self.0.crtc.0.crtc, display, surface)
+    }
+}
+
+#[cfg(all(feature = "backend_drm_atomic", feature = "backend_drm_legacy"))]
+unsafe impl<A: AsRawFd + 'static> NativeSurface
+    for EglStreamSurface<FallbackDevice<AtomicDrmDevice<A>, LegacyDrmDevice<A>>>
+{
+    type Error = Error<EitherError<DrmError, DrmError>>;
+
+    unsafe fn create(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attribs: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Self::Error>> {
+        let output_attributes = {
+            let mut out: Vec<isize> = Vec::with_capacity(3);
+            match &self.0.crtc {
+                FallbackSurface::Preference(dev) => {
+                    out.push(ffi::egl::DRM_PLANE_EXT as isize);
+                    out.push(Into::<u32>::into(dev.0.planes.primary) as isize);
+                } //AtomicDrmSurface
+                FallbackSurface::Fallback(dev) => {
+                    out.push(ffi::egl::DRM_CRTC_EXT as isize);
+                    out.push(Into::<u32>::into(dev.0.crtc) as isize);
+                } // LegacyDrmSurface
+            }
+            out.push(ffi::egl::NONE as isize);
+            out
+        };
+
+        self.create_surface(display, config_id, surface_attribs, &output_attributes)
+            .map_err(SurfaceCreationError::NativeSurfaceCreationFailed)
+    }
+
+    fn needs_recreation(&self) -> bool {
+        self.0.crtc.commit_pending()
+    }
+
+    fn swap_buffers(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        surface: ffi::egl::types::EGLSurface,
+    ) -> Result<(), SwapBuffersError<Self::Error>> {
+        if let Some((buffer, fb)) = self.0.commit_buffer.take() {
+            let _ = self.0.crtc.destroy_framebuffer(fb);
+            let _ = self.0.crtc.destroy_dumb_buffer(buffer);
+        }
+        let crtc = match &self.0.crtc {
+            FallbackSurface::Preference(dev) => dev.0.crtc,
+            FallbackSurface::Fallback(dev) => dev.0.crtc,
+        };
+
+        self.flip(crtc, display, surface)
+    }
+}

src/backend/drm/eglstream/mod.rs

@@ -0,0 +1,364 @@
+//!
+//! [`Device`](Device) and [`Surface`](Surface) implementations using
+//! the proposed EGLStream api for efficient rendering.
+//! Currently this api is only implemented by the proprietary `nvidia` driver.
+//!
+//! Usually this implementation will be wrapped into a [`EglDevice`](::backend::drm::egl::EglDevice).
+//!
+//! To use these types standalone, you will need to render via egl yourself as page flips
+//! are driven via `eglSwapBuffers`.
+//!
+//! To use this api in place of GBM for nvidia cards take a look at
+//! [`FallbackDevice`](::backend::drm::common::fallback::FallbackDevice).
+//! Take a look at `anvil`s source code for an example of this.
+//!
+
+use super::{Device, DeviceHandler, RawDevice, Surface};
+
+use drm::buffer::format::PixelFormat;
+use drm::control::{
+    connector, crtc, encoder, framebuffer, plane, Device as ControlDevice, Mode, ResourceHandles,
+};
+use drm::SystemError as DrmError;
+use failure::ResultExt;
+use nix::libc::dev_t;
+
+use std::cell::{Cell, RefCell};
+use std::collections::HashMap;
+use std::ffi::CStr;
+use std::os::unix::fs::MetadataExt;
+use std::os::unix::io::{AsRawFd, RawFd};
+use std::rc::{Rc, Weak};
+use std::{fs, ptr};
+
+mod surface;
+pub use self::surface::EglStreamSurface;
+use self::surface::EglStreamSurfaceInternal;
+
+pub mod egl;
+#[cfg(feature = "backend_session")]
+pub mod session;
+
+use crate::backend::egl::ffi::{self, egl::types::EGLDeviceEXT};
+use crate::backend::egl::{wrap_egl_call, EGLError as RawEGLError, Error as EglError};
+use crate::backend::graphics::SwapBuffersError;
+
+/// Errors thrown by the [`EglStreamDevice`](::backend::drm::eglstream::EglStreamDevice)
+/// and [`EglStreamSurface`](::backend::drm::eglstream::EglStreamSurface).
+#[derive(thiserror::Error, Debug)]
+pub enum Error<U: std::error::Error + std::fmt::Debug + std::fmt::Display + 'static> {
+    /// `eglInitialize` returned an error
+    #[error("Failed to initialize EGL: {0:}")]
+    InitFailed(#[source] RawEGLError),
+    /// Failed to enumerate EGL_EXT_drm_device
+    #[error("Failed to enumerate EGL_EXT_drm_device: {0:}")]
+    FailedToEnumerateDevices(#[source] RawEGLError),
+    /// Device is not compatible with EGL_EXT_drm_device extension
+    #[error("Device is not compatible with EGL_EXT_drm_device extension")]
+    DeviceIsNoEGLStreamDevice,
+    /// Device has not suitable output layer
+    #[error("Device has no suitable output layer")]
+    DeviceNoOutputLayer,
+    /// Device was unable to create an EGLStream
+    #[error("EGLStream creation failed")]
+    DeviceStreamCreationFailed,
+    /// Underlying backend  error
+    #[error("Underlying error: {0}")]
+    Underlying(#[source] U),
+    /// Buffer creation failed
+    #[error("Buffer creation failed")]
+    BufferCreationFailed(#[source] failure::Compat<DrmError>),
+    /// Buffer write failed
+    #[error("Buffer write failed")]
+    BufferWriteFailed(#[source] failure::Compat<DrmError>),
+    /// Stream flip failed
+    #[error("Stream flip failed ({0})")]
+    StreamFlipFailed(#[source] RawEGLError),
+}
+
+/// Representation of an open egl stream device to create egl rendering surfaces
+pub struct EglStreamDevice<D: RawDevice + ControlDevice + 'static> {
+    pub(self) dev: EGLDeviceEXT,
+    raw: D,
+    backends: Rc<RefCell<HashMap<crtc::Handle, Weak<EglStreamSurfaceInternal<D>>>>>,
+    logger: ::slog::Logger,
+}
+
+impl<D: RawDevice + ControlDevice + 'static> EglStreamDevice<D> {
+    /// Try to create a new [`EglStreamDevice`] from an open device.
+    ///
+    /// Returns an error if the underlying device would not support the required EGL extensions.
+    pub fn new<L>(mut raw: D, logger: L) -> Result<Self, Error<<<D as Device>::Surface as Surface>::Error>>
+    where
+        L: Into<Option<::slog::Logger>>,
+    {
+        let log = crate::slog_or_stdlog(logger).new(o!("smithay_module" => "backend_eglstream"));
+
+        raw.clear_handler();
+
+        debug!(log, "Creating egl stream device");
+
+        ffi::make_sure_egl_is_loaded();
+
+        fn has_extensions(exts: &[String], check: &'static [&'static str]) -> Result<(), EglError> {
+            check
+                .iter()
+                .map(|ext| {
+                    if exts.iter().any(|s| *s == *ext) {
+                        Ok(())
+                    } else {
+                        Err(EglError::EglExtensionNotSupported(check))
+                    }
+                })
+                .collect()
+        }
+
+        let device = unsafe {
+            // the first step is to query the list of extensions without any display, if supported
+            let dp_extensions = {
+                let p = wrap_egl_call(|| {
+                    ffi::egl::QueryString(ffi::egl::NO_DISPLAY, ffi::egl::EXTENSIONS as i32)
+                })
+                .map_err(Error::InitFailed)?;
+
+                // this possibility is available only with EGL 1.5 or EGL_EXT_platform_base, otherwise
+                // `eglQueryString` returns an error
+                if p.is_null() {
+                    vec![]
+                } else {
+                    let p = CStr::from_ptr(p);
+                    let list = String::from_utf8(p.to_bytes().to_vec()).unwrap_or_else(|_| String::new());
+                    list.split(' ').map(|e| e.to_string()).collect::<Vec<_>>()
+                }
+            };
+            debug!(log, "EGL No-Display Extensions: {:?}", dp_extensions);
+
+            // we need either EGL_EXT_device_base or EGL_EXT_device_enumeration &_query
+            if let Err(_err) = has_extensions(&dp_extensions, &["EGL_EXT_device_base"]) {
+                has_extensions(
+                    &dp_extensions,
+                    &["EGL_EXT_device_enumeration", "EGL_EXT_device_query"],
+                )
+                .map_err(|_| Error::DeviceIsNoEGLStreamDevice)?;
+            }
+
+            let mut num_devices = 0;
+            wrap_egl_call(|| ffi::egl::QueryDevicesEXT(0, ptr::null_mut(), &mut num_devices))
+                .map_err(Error::FailedToEnumerateDevices)?;
+            if num_devices == 0 {
+                return Err(Error::DeviceIsNoEGLStreamDevice);
+            }
+
+            let mut devices = Vec::with_capacity(num_devices as usize);
+            wrap_egl_call(|| ffi::egl::QueryDevicesEXT(num_devices, devices.as_mut_ptr(), &mut num_devices))
+                .map_err(Error::FailedToEnumerateDevices)?;
+            devices.set_len(num_devices as usize);
+            debug!(log, "Devices: {:#?}, Count: {}", devices, num_devices);
+
+            devices
+                .into_iter()
+                .find(|device| {
+                    *device != ffi::egl::NO_DEVICE_EXT
+                        && {
+                            let device_extensions = {
+                                let p = ffi::egl::QueryDeviceStringEXT(*device, ffi::egl::EXTENSIONS as i32);
+                                if p.is_null() {
+                                    vec![]
+                                } else {
+                                    let p = CStr::from_ptr(p);
+                                    let list = String::from_utf8(p.to_bytes().to_vec())
+                                        .unwrap_or_else(|_| String::new());
+                                    list.split(' ').map(|e| e.to_string()).collect::<Vec<_>>()
+                                }
+                            };
+
+                            device_extensions.iter().any(|s| *s == "EGL_EXT_device_drm")
+                        }
+                        && {
+                            let path = {
+                                let p = ffi::egl::QueryDeviceStringEXT(
+                                    *device,
+                                    ffi::egl::DRM_DEVICE_FILE_EXT as i32,
+                                );
+                                if p.is_null() {
+                                    String::new()
+                                } else {
+                                    let p = CStr::from_ptr(p);
+                                    String::from_utf8(p.to_bytes().to_vec()).unwrap_or_else(|_| String::new())
+                                }
+                            };
+
+                            match fs::metadata(&path) {
+                                Ok(metadata) => metadata.rdev() == raw.device_id(),
+                                Err(_) => false,
+                            }
+                        }
+                })
+                .ok_or(Error::DeviceIsNoEGLStreamDevice)?
+        };
+
+        Ok(EglStreamDevice {
+            dev: device,
+            raw,
+            backends: Rc::new(RefCell::new(HashMap::new())),
+            logger: log,
+        })
+    }
+}
+
+struct InternalDeviceHandler<D: RawDevice + ControlDevice + 'static> {
+    handler: Box<dyn DeviceHandler<Device = EglStreamDevice<D>> + 'static>,
+    backends: Weak<RefCell<HashMap<crtc::Handle, Weak<EglStreamSurfaceInternal<D>>>>>,
+    logger: ::slog::Logger,
+}
+
+impl<D: RawDevice + ControlDevice + 'static> DeviceHandler for InternalDeviceHandler<D> {
+    type Device = D;
+
+    fn vblank(&mut self, crtc: crtc::Handle) {
+        if let Some(backends) = self.backends.upgrade() {
+            if let Some(surface) = backends.borrow().get(&crtc) {
+                if surface.upgrade().is_some() {
+                    self.handler.vblank(crtc);
+                }
+            } else {
+                warn!(
+                    self.logger,
+                    "Surface ({:?}) not managed by egl stream, event not handled.", crtc
+                );
+            }
+        }
+    }
+    fn error(&mut self, error: <<D as Device>::Surface as Surface>::Error) {
+        self.handler.error(Error::Underlying(error))
+    }
+}
+
+impl<D: RawDevice + ControlDevice + 'static> Device for EglStreamDevice<D> {
+    type Surface = EglStreamSurface<D>;
+
+    fn device_id(&self) -> dev_t {
+        self.raw.device_id()
+    }
+
+    fn set_handler(&mut self, handler: impl DeviceHandler<Device = Self> + 'static) {
+        self.raw.set_handler(InternalDeviceHandler {
+            handler: Box::new(handler),
+            backends: Rc::downgrade(&self.backends),
+            logger: self.logger.clone(),
+        });
+    }
+
+    fn clear_handler(&mut self) {
+        self.raw.clear_handler();
+    }
+
+    fn create_surface(
+        &mut self,
+        crtc: crtc::Handle,
+        mode: Mode,
+        connectors: &[connector::Handle],
+    ) -> Result<EglStreamSurface<D>, Error<<<D as Device>::Surface as Surface>::Error>> {
+        info!(self.logger, "Initializing EglStreamSurface");
+
+        let drm_surface =
+            Device::create_surface(&mut self.raw, crtc, mode, connectors).map_err(Error::Underlying)?;
+
+        // initialize a buffer for the cursor image
+        let cursor = Cell::new(Some((
+            self.raw
+                .create_dumb_buffer((1, 1), PixelFormat::ARGB8888)
+                .compat()
+                .map_err(Error::BufferCreationFailed)?,
+            (0, 0),
+        )));
+
+        let backend = Rc::new(EglStreamSurfaceInternal {
+            crtc: drm_surface,
+            cursor,
+            stream: RefCell::new(None),
+            commit_buffer: Cell::new(None),
+            logger: self.logger.new(o!("crtc" => format!("{:?}", crtc))),
+            locked: std::sync::atomic::AtomicBool::new(false),
+        });
+        self.backends.borrow_mut().insert(crtc, Rc::downgrade(&backend));
+        Ok(EglStreamSurface(backend))
+    }
+
+    fn process_events(&mut self) {
+        self.raw.process_events()
+    }
+
+    fn resource_handles(&self) -> Result<ResourceHandles, Error<<<D as Device>::Surface as Surface>::Error>> {
+        Device::resource_handles(&self.raw).map_err(Error::Underlying)
+    }
+
+    fn get_connector_info(&self, conn: connector::Handle) -> Result<connector::Info, DrmError> {
+        self.raw.get_connector_info(conn)
+    }
+    fn get_crtc_info(&self, crtc: crtc::Handle) -> Result<crtc::Info, DrmError> {
+        self.raw.get_crtc_info(crtc)
+    }
+    fn get_encoder_info(&self, enc: encoder::Handle) -> Result<encoder::Info, DrmError> {
+        self.raw.get_encoder_info(enc)
+    }
+    fn get_framebuffer_info(&self, fb: framebuffer::Handle) -> Result<framebuffer::Info, DrmError> {
+        self.raw.get_framebuffer_info(fb)
+    }
+    fn get_plane_info(&self, plane: plane::Handle) -> Result<plane::Info, DrmError> {
+        self.raw.get_plane_info(plane)
+    }
+}
+
+impl<D: RawDevice + ControlDevice + 'static> AsRawFd for EglStreamDevice<D> {
+    fn as_raw_fd(&self) -> RawFd {
+        self.raw.as_raw_fd()
+    }
+}
+
+impl<D: RawDevice + ControlDevice + 'static> Drop for EglStreamDevice<D> {
+    fn drop(&mut self) {
+        self.clear_handler();
+    }
+}
+
+impl<E> Into<SwapBuffersError> for Error<E>
+where
+    E: std::error::Error + Into<SwapBuffersError> + 'static,
+{
+    fn into(self) -> SwapBuffersError {
+        match self {
+            Error::BufferCreationFailed(x)
+                if match x.get_ref() {
+                    drm::SystemError::Unknown {
+                        errno: nix::errno::Errno::EBUSY,
+                    } => true,
+                    drm::SystemError::Unknown {
+                        errno: nix::errno::Errno::EINTR,
+                    } => true,
+                    _ => false,
+                } =>
+            {
+                SwapBuffersError::TemporaryFailure(Box::new(Error::<E>::BufferCreationFailed(x)))
+            }
+            Error::BufferWriteFailed(x)
+                if match x.get_ref() {
+                    drm::SystemError::Unknown {
+                        errno: nix::errno::Errno::EBUSY,
+                    } => true,
+                    drm::SystemError::Unknown {
+                        errno: nix::errno::Errno::EINTR,
+                    } => true,
+                    _ => false,
+                } =>
+            {
+                SwapBuffersError::TemporaryFailure(Box::new(Error::<E>::BufferCreationFailed(x)))
+            }
+            Error::StreamFlipFailed(x @ RawEGLError::ResourceBusy) => {
+                SwapBuffersError::TemporaryFailure(Box::new(Error::<E>::StreamFlipFailed(x)))
+            }
+            Error::Underlying(x) => x.into(),
+            x => SwapBuffersError::ContextLost(Box::new(x)),
+        }
+    }
+}

src/backend/drm/eglstream/session.rs

@@ -0,0 +1,91 @@
+//!
+//! Support to register a [`EglStreamDevice`](EglStreamDevice)
+//! to an open [`Session`](::backend::session::Session).
+//!
+
+use super::{EglStreamDevice, EglStreamSurfaceInternal};
+use crate::backend::drm::{RawDevice, Surface};
+use crate::backend::egl::ffi;
+use crate::backend::session::{AsSessionObserver, SessionObserver};
+
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::os::unix::io::RawFd;
+use std::rc::{Rc, Weak};
+
+use drm::control::{crtc, Device as ControlDevice};
+
+/// [`SessionObserver`](SessionObserver)
+/// linked to the [`EglStreamDevice`](EglStreamDevice) it was
+/// created from.
+pub struct EglStreamDeviceObserver<
+    O: SessionObserver + 'static,
+    D: RawDevice + AsSessionObserver<O> + 'static,
+> {
+    observer: O,
+    backends: Weak<RefCell<HashMap<crtc::Handle, Weak<EglStreamSurfaceInternal<D>>>>>,
+    logger: ::slog::Logger,
+}
+
+impl<O: SessionObserver + 'static, D: RawDevice + ControlDevice + AsSessionObserver<O> + 'static>
+    AsSessionObserver<EglStreamDeviceObserver<O, D>> for EglStreamDevice<D>
+{
+    fn observer(&mut self) -> EglStreamDeviceObserver<O, D> {
+        EglStreamDeviceObserver {
+            observer: self.raw.observer(),
+            backends: Rc::downgrade(&self.backends),
+            logger: self.logger.clone(),
+        }
+    }
+}
+
+impl<O: SessionObserver + 'static, D: RawDevice + AsSessionObserver<O> + 'static> SessionObserver
+    for EglStreamDeviceObserver<O, D>
+{
+    fn pause(&mut self, devnum: Option<(u32, u32)>) {
+        if let Some(backends) = self.backends.upgrade() {
+            for (_, backend) in backends.borrow().iter() {
+                if let Some(backend) = backend.upgrade() {
+                    // destroy/disable the streams so it will not submit any pending frames
+                    if let Some((display, stream)) = backend.stream.replace(None) {
+                        unsafe {
+                            ffi::egl::DestroyStreamKHR(display.handle, stream);
+                        }
+                    }
+                    // framebuffers will be likely not valid anymore, lets just recreate those after activation.
+                    if let Some((buffer, fb)) = backend.commit_buffer.take() {
+                        let _ = backend.crtc.destroy_framebuffer(fb);
+                        let _ = backend.crtc.destroy_dumb_buffer(buffer);
+                    }
+                }
+            }
+        }
+
+        self.observer.pause(devnum);
+    }
+
+    fn activate(&mut self, devnum: Option<(u32, u32, Option<RawFd>)>) {
+        self.observer.activate(devnum);
+        if let Some(backends) = self.backends.upgrade() {
+            for (_, backend) in backends.borrow().iter() {
+                if let Some(backend) = backend.upgrade() {
+                    if let Some((cursor, hotspot)) = backend.cursor.get() {
+                        if backend
+                            .crtc
+                            .set_cursor2(
+                                backend.crtc.crtc(),
+                                Some(&cursor),
+                                (hotspot.0 as i32, hotspot.1 as i32),
+                            )
+                            .is_err()
+                        {
+                            if let Err(err) = backend.crtc.set_cursor(backend.crtc.crtc(), Some(&cursor)) {
+                                warn!(self.logger, "Failed to reset cursor: {}", err)
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

src/backend/drm/eglstream/surface.rs

@@ -0,0 +1,528 @@
+use super::super::{Device, RawDevice, RawSurface, Surface};
+use super::Error;
+
+use drm::buffer::format::PixelFormat;
+use drm::control::{connector, crtc, dumbbuffer::DumbBuffer, framebuffer, Device as ControlDevice, Mode};
+#[cfg(feature = "backend_drm")]
+use failure::ResultExt;
+#[cfg(feature = "backend_drm")]
+use image::{ImageBuffer, Rgba};
+use nix::libc::{c_int, c_void};
+
+use std::cell::{Cell, RefCell};
+use std::ffi::CStr;
+use std::ptr;
+use std::rc::Rc;
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
+
+#[cfg(feature = "backend_drm")]
+use crate::backend::drm::common::Error as DrmError;
+#[cfg(feature = "backend_drm")]
+use crate::backend::drm::DevPath;
+use crate::backend::egl::ffi::{
+    self,
+    egl::{self, types::EGLStreamKHR},
+};
+use crate::backend::egl::{display::EGLDisplayHandle, wrap_egl_call, EGLError, SwapBuffersError};
+#[cfg(feature = "backend_drm")]
+use crate::backend::graphics::CursorBackend;
+
+pub(in crate::backend::drm) struct EglStreamSurfaceInternal<D: RawDevice + 'static> {
+    pub(in crate::backend::drm) crtc: <D as Device>::Surface,
+    pub(in crate::backend::drm) cursor: Cell<Option<(DumbBuffer, (u32, u32))>>,
+    pub(in crate::backend::drm) stream: RefCell<Option<(Arc<EGLDisplayHandle>, EGLStreamKHR)>>,
+    pub(in crate::backend::drm) commit_buffer: Cell<Option<(DumbBuffer, framebuffer::Handle)>>,
+    pub(in crate::backend::drm) locked: AtomicBool,
+    pub(in crate::backend::drm) logger: ::slog::Logger,
+}
+
+impl<D: RawDevice + 'static> Surface for EglStreamSurfaceInternal<D> {
+    type Connectors = <<D as Device>::Surface as Surface>::Connectors;
+    type Error = Error<<<D as Device>::Surface as Surface>::Error>;
+
+    fn crtc(&self) -> crtc::Handle {
+        self.crtc.crtc()
+    }
+
+    fn current_connectors(&self) -> Self::Connectors {
+        self.crtc.current_connectors()
+    }
+
+    fn pending_connectors(&self) -> Self::Connectors {
+        self.crtc.pending_connectors()
+    }
+
+    fn add_connector(&self, connector: connector::Handle) -> Result<(), Self::Error> {
+        self.crtc.add_connector(connector).map_err(Error::Underlying)
+    }
+
+    fn remove_connector(&self, connector: connector::Handle) -> Result<(), Self::Error> {
+        self.crtc.remove_connector(connector).map_err(Error::Underlying)
+    }
+
+    fn set_connectors(&self, connectors: &[connector::Handle]) -> Result<(), Self::Error> {
+        self.crtc.set_connectors(connectors).map_err(Error::Underlying)
+    }
+
+    fn current_mode(&self) -> Mode {
+        self.crtc.current_mode()
+    }
+
+    fn pending_mode(&self) -> Mode {
+        self.crtc.pending_mode()
+    }
+
+    fn use_mode(&self, mode: Mode) -> Result<(), Error<<<D as Device>::Surface as Surface>::Error>> {
+        self.crtc.use_mode(mode).map_err(Error::Underlying)
+    }
+}
+
+impl<D: RawDevice + 'static> Drop for EglStreamSurfaceInternal<D> {
+    fn drop(&mut self) {
+        if let Some((buffer, _)) = self.cursor.get() {
+            let _ = self.crtc.destroy_dumb_buffer(buffer);
+        }
+        if let Some((buffer, fb)) = self.commit_buffer.take() {
+            let _ = self.crtc.destroy_framebuffer(fb);
+            let _ = self.crtc.destroy_dumb_buffer(buffer);
+        }
+        if let Some((display, stream)) = self.stream.replace(None) {
+            unsafe {
+                egl::DestroyStreamKHR(display.handle, stream);
+            }
+        }
+    }
+}
+
+// Conceptionally EglStream is a weird api.
+// It does modesetting on its own, bypassing our `RawSurface::commit` function.
+// As a result, we cannot easily sync any other planes to the commit without more
+// experimental egl extensions to do this via the EglStream-API.
+//
+// So instead we leverage the fact, that all drm-drivers still support the legacy
+// `drmModeSetCursor` and `drmModeMoveCursor` functions, that (mostly) implicitly sync to the primary plane.
+// That way we can use hardware cursors at least on all drm-backends (including atomic), although
+// this is a little hacky. Overlay planes however are completely out of question for now.
+//
+// Note that this might still appear a little chuppy, we should just use software cursors
+// on eglstream devices by default and only use this, if the user really wants it.
+#[cfg(feature = "backend_drm")]
+impl<D: RawDevice + 'static> CursorBackend for EglStreamSurfaceInternal<D> {
+    type CursorFormat = ImageBuffer<Rgba<u8>, Vec<u8>>;
+    type Error = Error<DrmError>;
+
+    fn set_cursor_position(&self, x: u32, y: u32) -> Result<(), Self::Error> {
+        trace!(self.logger, "Move the cursor to {},{}", x, y);
+        self.crtc
+            .move_cursor(self.crtc.crtc(), (x as i32, y as i32))
+            .compat()
+            .map_err(|source| DrmError::Access {
+                errmsg: "Error moving cursor",
+                dev: self.crtc.dev_path(),
+                source,
+            })
+            .map_err(Error::Underlying)
+    }
+
+    fn set_cursor_representation(
+        &self,
+        buffer: &ImageBuffer<Rgba<u8>, Vec<u8>>,
+        hotspot: (u32, u32),
+    ) -> Result<(), Self::Error> {
+        let (w, h) = buffer.dimensions();
+        debug!(self.logger, "Importing cursor");
+
+        // import the cursor into a buffer we can render
+        let mut cursor = self
+            .crtc
+            .create_dumb_buffer((w, h), PixelFormat::ARGB8888)
+            .compat()
+            .map_err(Error::BufferCreationFailed)?;
+
+        {
+            let mut mapping = self
+                .crtc
+                .map_dumb_buffer(&mut cursor)
+                .compat()
+                .map_err(Error::BufferWriteFailed)?;
+            mapping.as_mut().copy_from_slice(buffer);
+        }
+
+        trace!(self.logger, "Setting the new imported cursor");
+
+        trace!(self.logger, "Setting the new imported cursor");
+
+        if self
+            .crtc
+            .set_cursor2(
+                self.crtc.crtc(),
+                Some(&cursor),
+                (hotspot.0 as i32, hotspot.1 as i32),
+            )
+            .is_err()
+        {
+            self.crtc
+                .set_cursor(self.crtc.crtc(), Some(&cursor))
+                .compat()
+                .map_err(|source| DrmError::Access {
+                    errmsg: "Failed to set cursor",
+                    dev: self.crtc.dev_path(),
+                    source,
+                })
+                .map_err(Error::Underlying)?;
+        }
+
+        // and store it
+        if let Some((old, _)) = self.cursor.replace(Some((cursor, hotspot))) {
+            if self.crtc.destroy_dumb_buffer(old).is_err() {
+                warn!(self.logger, "Failed to free old cursor");
+            }
+        }
+
+        Ok(())
+    }
+}
+
+/// egl stream surface for rendering
+pub struct EglStreamSurface<D: RawDevice + 'static>(
+    pub(in crate::backend::drm) Rc<EglStreamSurfaceInternal<D>>,
+);
+
+impl<D: RawDevice + 'static> EglStreamSurface<D> {
+    /// Check if underlying gbm resources need to be recreated.
+    pub fn needs_recreation(&self) -> bool {
+        self.0.crtc.commit_pending() || self.0.stream.borrow().is_none()
+    }
+
+    pub(super) fn create_stream(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        output_attribs: &[isize],
+    ) -> Result<EGLStreamKHR, Error<<<D as Device>::Surface as Surface>::Error>> {
+        // drop old steam, if it already exists
+        if let Some((display, stream)) = self.0.stream.replace(None) {
+            // ignore result
+            unsafe {
+                ffi::egl::DestroyStreamKHR(display.handle, stream);
+            }
+        }
+
+        // because we are re-creating there might be a new mode. if there is? -> commit it
+        if self.0.crtc.commit_pending() {
+            let (w, h) = self.pending_mode().size();
+            // but we need a buffer to commit...
+            // well lets create one and clean it up once the stream is running
+            if let Ok(buffer) = self
+                .0
+                .crtc
+                .create_dumb_buffer((w as u32, h as u32), PixelFormat::ARGB8888)
+            {
+                if let Ok(fb) = self.0.crtc.add_framebuffer(&buffer) {
+                    if let Some((buffer, fb)) = self.0.commit_buffer.replace(Some((buffer, fb))) {
+                        let _ = self.0.crtc.destroy_framebuffer(fb);
+                        let _ = self.0.crtc.destroy_dumb_buffer(buffer);
+                    }
+                    self.0.crtc.commit(fb).map_err(Error::Underlying)?;
+                }
+            }
+        }
+
+        let extensions = {
+            let p =
+                unsafe { CStr::from_ptr(ffi::egl::QueryString(display.handle, ffi::egl::EXTENSIONS as i32)) };
+            let list = String::from_utf8(p.to_bytes().to_vec()).unwrap_or_else(|_| String::new());
+            list.split(' ').map(|e| e.to_string()).collect::<Vec<_>>()
+        };
+
+        if !extensions.iter().any(|s| *s == "EGL_EXT_output_base")
+            || !extensions.iter().any(|s| *s == "EGL_EXT_output_drm")
+            || !extensions.iter().any(|s| *s == "EGL_KHR_stream")
+            || !extensions
+                .iter()
+                .any(|s| *s == "EGL_EXT_stream_consumer_egloutput")
+            || !extensions
+                .iter()
+                .any(|s| *s == "EGL_KHR_stream_producer_eglsurface")
+        {
+            error!(self.0.logger, "Extension for EGLStream surface creation missing");
+            return Err(Error::DeviceIsNoEGLStreamDevice);
+        }
+
+        if cfg!(debug_assertions) {
+            // TEST START
+            let mut num_layers = 0;
+            if unsafe {
+                ffi::egl::GetOutputLayersEXT(
+                    display.handle,
+                    ptr::null(),
+                    ptr::null_mut(),
+                    10,
+                    &mut num_layers,
+                )
+            } == 0
+            {
+                error!(self.0.logger, "Failed to get any! output layer");
+            }
+            if num_layers == 0 {
+                error!(self.0.logger, "Failed to find any! output layer");
+            }
+            let mut layers = Vec::with_capacity(num_layers as usize);
+            if unsafe {
+                ffi::egl::GetOutputLayersEXT(
+                    display.handle,
+                    ptr::null(),
+                    layers.as_mut_ptr(),
+                    num_layers,
+                    &mut num_layers,
+                )
+            } == 0
+            {
+                error!(self.0.logger, "Failed to receive Output Layers");
+            }
+            unsafe {
+                layers.set_len(num_layers as usize);
+            }
+            for layer in layers {
+                debug!(self.0.logger, "Found layer: {:?}", layer);
+                let mut val = 0;
+                if unsafe {
+                    ffi::egl::QueryOutputLayerAttribEXT(
+                        display.handle,
+                        layer,
+                        ffi::egl::DRM_CRTC_EXT as i32,
+                        &mut val,
+                    )
+                } != 0
+                {
+                    info!(self.0.logger, "Possible crtc output layer: {}", val);
+                }
+                val = 0;
+                if unsafe {
+                    ffi::egl::QueryOutputLayerAttribEXT(
+                        display.handle,
+                        layer,
+                        ffi::egl::DRM_PLANE_EXT as i32,
+                        &mut val,
+                    )
+                } != 0
+                {
+                    info!(self.0.logger, "Possible plane output layer: {}", val);
+                }
+            }
+            // TEST END
+        }
+
+        let mut num_layers = 0;
+        if unsafe {
+            ffi::egl::GetOutputLayersEXT(
+                display.handle,
+                output_attribs.as_ptr(),
+                ptr::null_mut(),
+                1,
+                &mut num_layers,
+            )
+        } == 0
+        {
+            error!(
+                self.0.logger,
+                "Failed to acquire Output Layer. Attributes {:?}", output_attribs
+            );
+            return Err(Error::DeviceNoOutputLayer);
+        }
+        if num_layers == 0 {
+            error!(self.0.logger, "Failed to find Output Layer");
+            return Err(Error::DeviceNoOutputLayer);
+        }
+        let mut layers = Vec::with_capacity(num_layers as usize);
+        if unsafe {
+            ffi::egl::GetOutputLayersEXT(
+                display.handle,
+                output_attribs.as_ptr(),
+                layers.as_mut_ptr(),
+                num_layers,
+                &mut num_layers,
+            )
+        } == 0
+        {
+            error!(self.0.logger, "Failed to get Output Layer");
+            return Err(Error::DeviceNoOutputLayer);
+        }
+        unsafe {
+            layers.set_len(num_layers as usize);
+        }
+
+        let layer = layers[0];
+        unsafe {
+            ffi::egl::OutputLayerAttribEXT(display.handle, layer, ffi::egl::SWAP_INTERVAL_EXT as i32, 0);
+        }
+
+        let stream_attributes = {
+            let mut out: Vec<c_int> = Vec::with_capacity(7);
+            out.push(ffi::egl::STREAM_FIFO_LENGTH_KHR as i32);
+            out.push(0);
+            out.push(ffi::egl::CONSUMER_AUTO_ACQUIRE_EXT as i32);
+            out.push(ffi::egl::FALSE as i32);
+            out.push(ffi::egl::CONSUMER_ACQUIRE_TIMEOUT_USEC_KHR as i32);
+            out.push(0);
+            out.push(ffi::egl::NONE as i32);
+            out
+        };
+
+        let stream = unsafe { ffi::egl::CreateStreamKHR(display.handle, stream_attributes.as_ptr()) };
+        if stream == ffi::egl::NO_STREAM_KHR {
+            error!(self.0.logger, "Failed to create egl stream");
+            return Err(Error::DeviceStreamCreationFailed);
+        }
+
+        if unsafe { ffi::egl::StreamConsumerOutputEXT(display.handle, stream, layer) } == 0 {
+            error!(self.0.logger, "Failed to link Output Layer as Stream Consumer");
+            return Err(Error::DeviceStreamCreationFailed);
+        }
+
+        let _ = self.0.stream.replace(Some((display.clone(), stream)));
+
+        Ok(stream)
+    }
+
+    pub(super) fn create_surface(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        _surface_attribs: &[c_int],
+        output_attribs: &[isize],
+    ) -> Result<*const c_void, Error<<<D as Device>::Surface as Surface>::Error>> {
+        let stream = self.create_stream(display, output_attribs)?;
+
+        let (w, h) = self.current_mode().size();
+        info!(self.0.logger, "Creating stream surface with size: ({}:{})", w, h);
+        let surface_attributes = {
+            let mut out: Vec<c_int> = Vec::with_capacity(5);
+            out.push(ffi::egl::WIDTH as i32);
+            out.push(w as i32);
+            out.push(ffi::egl::HEIGHT as i32);
+            out.push(h as i32);
+            out.push(ffi::egl::NONE as i32);
+            out
+        };
+
+        let surface = unsafe {
+            ffi::egl::CreateStreamProducerSurfaceKHR(
+                display.handle,
+                config_id,
+                stream,
+                surface_attributes.as_ptr(),
+            )
+        };
+        if surface == ffi::egl::NO_SURFACE {
+            error!(self.0.logger, "Failed to create surface: 0x{:X}", unsafe {
+                ffi::egl::GetError()
+            });
+        }
+        Ok(surface)
+    }
+
+    pub(super) fn flip(
+        &self,
+        crtc: crtc::Handle,
+        display: &Arc<EGLDisplayHandle>,
+        surface: ffi::egl::types::EGLSurface,
+    ) -> Result<(), SwapBuffersError<Error<<<D as Device>::Surface as Surface>::Error>>> {
+        if self.0.locked.load(Ordering::SeqCst) {
+            let acquire_attributes = [
+                ffi::egl::DRM_FLIP_EVENT_DATA_NV as isize,
+                Into::<u32>::into(crtc) as isize,
+                ffi::egl::NONE as isize,
+            ];
+
+            if let Ok(stream) = self.0.stream.try_borrow() {
+                let res = if let Some(&(ref display, ref stream)) = stream.as_ref() {
+                    wrap_egl_call(|| unsafe {
+                        ffi::egl::StreamConsumerAcquireAttribNV(
+                            display.handle,
+                            *stream,
+                            acquire_attributes.as_ptr(),
+                        );
+                    })
+                    .map_err(Error::StreamFlipFailed)
+                } else {
+                    Err(Error::StreamFlipFailed(EGLError::NotInitialized))
+                };
+                if res.is_ok() {
+                    self.0.locked.store(false, Ordering::SeqCst);
+                } else {
+                    return res.map_err(SwapBuffersError::Underlying);
+                }
+            }
+        }
+
+        if !self.0.locked.load(Ordering::SeqCst) {
+            wrap_egl_call(|| unsafe { ffi::egl::SwapBuffers(***display, surface as *const _) })
+                .map_err(SwapBuffersError::EGLSwapBuffers)?;
+            self.0.locked.store(true, Ordering::SeqCst);
+        }
+
+        Ok(())
+    }
+}
+
+impl<D: RawDevice + 'static> Surface for EglStreamSurface<D> {
+    type Connectors = <<D as Device>::Surface as Surface>::Connectors;
+    type Error = Error<<<D as Device>::Surface as Surface>::Error>;
+
+    fn crtc(&self) -> crtc::Handle {
+        self.0.crtc()
+    }
+
+    fn current_connectors(&self) -> Self::Connectors {
+        self.0.current_connectors()
+    }
+
+    fn pending_connectors(&self) -> Self::Connectors {
+        self.0.pending_connectors()
+    }
+
+    fn add_connector(&self, connector: connector::Handle) -> Result<(), Self::Error> {
+        self.0.add_connector(connector)
+    }
+
+    fn remove_connector(&self, connector: connector::Handle) -> Result<(), Self::Error> {
+        self.0.remove_connector(connector)
+    }
+
+    fn set_connectors(&self, connectors: &[connector::Handle]) -> Result<(), Self::Error> {
+        self.0.set_connectors(connectors)
+    }
+
+    fn current_mode(&self) -> Mode {
+        self.0.current_mode()
+    }
+
+    fn pending_mode(&self) -> Mode {
+        self.0.pending_mode()
+    }
+
+    fn use_mode(&self, mode: Mode) -> Result<(), Self::Error> {
+        self.0.use_mode(mode)
+    }
+}
+
+#[cfg(feature = "backend_drm_legacy")]
+impl<D: RawDevice + 'static> CursorBackend for EglStreamSurface<D> {
+    type CursorFormat = ImageBuffer<Rgba<u8>, Vec<u8>>;
+    type Error = Error<DrmError>;
+
+    fn set_cursor_position(&self, x: u32, y: u32) -> Result<(), Self::Error> {
+        self.0.set_cursor_position(x, y)
+    }
+
+    fn set_cursor_representation(
+        &self,
+        buffer: &ImageBuffer<Rgba<u8>, Vec<u8>>,
+        hotspot: (u32, u32),
+    ) -> Result<(), Self::Error> {
+        self.0.set_cursor_representation(buffer, hotspot)
+    }
+}

src/backend/drm/gbm/egl.rs

@@ -5,16 +5,19 @@
 //!
 
 use crate::backend::drm::{Device, RawDevice, Surface};
-use crate::backend::egl::ffi;
 use crate::backend::egl::native::{Backend, NativeDisplay, NativeSurface};
-use crate::backend::egl::{wrap_egl_call, EGLError, Error as EglBackendError};
+use crate::backend::egl::{display::EGLDisplayHandle, ffi};
+use crate::backend::egl::{
+    wrap_egl_call, EGLError, Error as EglBackendError, SurfaceCreationError, SwapBuffersError,
+};
 
 use super::{Error, GbmDevice, GbmSurface};
 
 use drm::control::{connector, crtc, Device as ControlDevice, Mode};
 use gbm::AsRaw;
+use nix::libc::{c_int, c_void};
 use std::marker::PhantomData;
-use std::ptr;
+use std::sync::Arc;
 
 /// Egl Gbm backend type
 ///
@@ -25,9 +28,11 @@ pub struct Gbm<D: RawDevice + 'static> {
 
 impl<D: RawDevice + 'static> Backend for Gbm<D> {
     type Surface = GbmSurface<D>;
+    type Error = Error<<<D as Device>::Surface as Surface>::Error>;
 
     unsafe fn get_display<F>(
         display: ffi::NativeDisplayType,
+        attribs: &[ffi::EGLint],
         has_dp_extension: F,
         log: ::slog::Logger,
     ) -> Result<ffi::egl::types::EGLDisplay, EGLError>
@@ -36,29 +41,33 @@ impl<D: RawDevice + 'static> Backend for Gbm<D> {
     {
         if has_dp_extension("EGL_KHR_platform_gbm") && ffi::egl::GetPlatformDisplay::is_loaded() {
             trace!(log, "EGL Display Initialization via EGL_KHR_platform_gbm");
+            let attribs = attribs.iter().map(|x| *x as isize).collect::<Vec<_>>();
             wrap_egl_call(|| {
-                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_GBM_KHR, display as *mut _, ptr::null())
+                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_GBM_KHR, display as *mut _, attribs.as_ptr())
             })
         } else if has_dp_extension("EGL_MESA_platform_gbm") && ffi::egl::GetPlatformDisplayEXT::is_loaded() {
             trace!(log, "EGL Display Initialization via EGL_MESA_platform_gbm");
             wrap_egl_call(|| {
-                ffi::egl::GetPlatformDisplayEXT(ffi::egl::PLATFORM_GBM_MESA, display as *mut _, ptr::null())
+                ffi::egl::GetPlatformDisplayEXT(
+                    ffi::egl::PLATFORM_GBM_MESA,
+                    display as *mut _,
+                    attribs.as_ptr(),
+                )
             })
         } else if has_dp_extension("EGL_MESA_platform_gbm") && ffi::egl::GetPlatformDisplay::is_loaded() {
             trace!(log, "EGL Display Initialization via EGL_MESA_platform_gbm");
+            let attribs = attribs.iter().map(|x| *x as isize).collect::<Vec<_>>();
             wrap_egl_call(|| {
-                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_GBM_MESA, display as *mut _, ptr::null())
+                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_GBM_MESA, display as *mut _, attribs.as_ptr())
             })
         } else {
-            trace!(log, "Default EGL Display Initialization via GetDisplay");
+            Ok(ffi::egl::NO_DISPLAY)
-            wrap_egl_call(|| ffi::egl::GetDisplay(display as *mut _))
         }
     }
 }
 
 unsafe impl<D: RawDevice + ControlDevice + 'static> NativeDisplay<Gbm<D>> for GbmDevice<D> {
     type Arguments = (crtc::Handle, Mode, Vec<connector::Handle>);
-    type Error = Error<<<D as Device>::Surface as Surface>::Error>;
 
     fn is_backend(&self) -> bool {
         true
@@ -68,29 +77,49 @@ unsafe impl<D: RawDevice + ControlDevice + 'static> NativeDisplay<Gbm<D>> for Gb
         Ok(self.dev.borrow().as_raw() as *const _)
     }
 
-    fn create_surface(&mut self, args: Self::Arguments) -> Result<GbmSurface<D>, Self::Error> {
+    fn create_surface(
+        &mut self,
+        args: Self::Arguments,
+    ) -> Result<GbmSurface<D>, Error<<<D as Device>::Surface as Surface>::Error>> {
         Device::create_surface(self, args.0, args.1, &args.2)
     }
 }
 
 unsafe impl<D: RawDevice + 'static> NativeSurface for GbmSurface<D> {
-    type Error = Error<<<D as RawDevice>::Surface as Surface>::Error>;
+    type Error = Error<<<D as Device>::Surface as Surface>::Error>;
 
-    fn ptr(&self) -> ffi::NativeWindowType {
+    unsafe fn create(
-        self.0.surface.borrow().as_raw() as *const _
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attributes: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Self::Error>> {
+        GbmSurface::recreate(self).map_err(SurfaceCreationError::NativeSurfaceCreationFailed)?;
+
+        wrap_egl_call(|| {
+            ffi::egl::CreateWindowSurface(
+                display.handle,
+                config_id,
+                self.0.surface.borrow().as_raw() as *const _,
+                surface_attributes.as_ptr(),
+            )
+        })
+        .map_err(SurfaceCreationError::EGLSurfaceCreationFailed)
     }
 
     fn needs_recreation(&self) -> bool {
         self.needs_recreation()
     }
 
-    fn recreate(&self) -> Result<(), Self::Error> {
+    fn swap_buffers(
-        GbmSurface::recreate(self)
+        &self,
-    }
+        display: &Arc<EGLDisplayHandle>,
-
+        surface: ffi::egl::types::EGLSurface,
-    fn swap_buffers(&self) -> Result<(), Self::Error> {
+    ) -> Result<(), SwapBuffersError<Self::Error>> {
+        wrap_egl_call(|| unsafe { ffi::egl::SwapBuffers(***display, surface as *const _) })
+            .map_err(SwapBuffersError::EGLSwapBuffers)?;
         // this is safe since `eglSwapBuffers` will have been called exactly once
         // if this is used by our egl module, which is why this trait is unsafe.
-        unsafe { self.page_flip() }
+        unsafe { self.page_flip() }.map_err(SwapBuffersError::Underlying)
     }
 }

src/backend/drm/legacy/surface.rs

@@ -23,9 +23,9 @@ pub struct State {
     pub connectors: HashSet<connector::Handle>,
 }
 
-pub(super) struct LegacyDrmSurfaceInternal<A: AsRawFd + 'static> {
+pub(in crate::backend::drm) struct LegacyDrmSurfaceInternal<A: AsRawFd + 'static> {
     pub(super) dev: Rc<Dev<A>>,
-    pub(super) crtc: crtc::Handle,
+    pub(in crate::backend::drm) crtc: crtc::Handle,
     pub(super) state: RwLock<State>,
     pub(super) pending: RwLock<State>,
     pub(super) logger: ::slog::Logger,
@@ -454,7 +454,9 @@ impl<A: AsRawFd + 'static> Drop for LegacyDrmSurfaceInternal<A> {
 }
 
 /// Open raw crtc utilizing legacy mode-setting
-pub struct LegacyDrmSurface<A: AsRawFd + 'static>(pub(super) Rc<LegacyDrmSurfaceInternal<A>>);
+pub struct LegacyDrmSurface<A: AsRawFd + 'static>(
+    pub(in crate::backend::drm) Rc<LegacyDrmSurfaceInternal<A>>,
+);
 
 impl<A: AsRawFd + 'static> AsRawFd for LegacyDrmSurface<A> {
     fn as_raw_fd(&self) -> RawFd {

src/backend/drm/mod.rs

@@ -54,6 +54,8 @@ pub mod atomic;
 pub mod common;
 #[cfg(feature = "backend_drm_egl")]
 pub mod egl;
+#[cfg(feature = "backend_drm_eglstream")]
+pub mod eglstream;
 #[cfg(feature = "backend_drm_gbm")]
 pub mod gbm;
 #[cfg(feature = "backend_drm_legacy")]

src/backend/egl/display.rs

@@ -8,9 +8,7 @@ use crate::backend::egl::{
 };
 use std::sync::Arc;
 
-use std::ptr;
+use nix::libc::c_int;
-
-use nix::libc::{c_int, c_void};
 
 #[cfg(feature = "wayland_frontend")]
 use wayland_server::{protocol::wl_buffer::WlBuffer, Display};
@@ -22,7 +20,7 @@ use crate::backend::egl::context::{GlAttributes, PixelFormatRequirements};
 use crate::backend::graphics::gl::ffi as gl_ffi;
 use crate::backend::graphics::PixelFormat;
 use std::cell::{Ref, RefCell, RefMut};
-use std::ffi::{CStr, CString};
+use std::ffi::CStr;
 use std::marker::PhantomData;
 use std::mem::MaybeUninit;
 
@@ -30,8 +28,9 @@ use std::ops::Deref;
 
 /// Wrapper around [`ffi::EGLDisplay`](ffi::egl::types::EGLDisplay) to ensure display is only destroyed
 /// once all resources bound to it have been dropped.
-pub(crate) struct EGLDisplayHandle {
+pub struct EGLDisplayHandle {
-    handle: ffi::egl::types::EGLDisplay,
+    /// ffi EGLDisplay ptr
+    pub handle: ffi::egl::types::EGLDisplay,
 }
 
 impl Deref for EGLDisplayHandle {
@@ -69,29 +68,9 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
     {
         let log = crate::slog_or_stdlog(logger.into()).new(o!("smithay_module" => "renderer_egl"));
         let ptr = native.ptr()?;
+        let egl_attribs = native.attributes();
 
-        ffi::egl::LOAD.call_once(|| unsafe {
+        ffi::make_sure_egl_is_loaded();
-            fn constrain<F>(f: F) -> F
-            where
-                F: for<'a> Fn(&'a str) -> *const ::std::os::raw::c_void,
-            {
-                f
-            };
-
-            ffi::egl::load_with(|sym| {
-                let name = CString::new(sym).unwrap();
-                let symbol = ffi::egl::LIB.get::<*mut c_void>(name.as_bytes());
-                match symbol {
-                    Ok(x) => *x as *const _,
-                    Err(_) => ptr::null(),
-                }
-            });
-            let proc_address = constrain(|sym| get_proc_address(sym));
-            ffi::egl::load_with(&proc_address);
-            ffi::egl::BindWaylandDisplayWL::load_with(&proc_address);
-            ffi::egl::UnbindWaylandDisplayWL::load_with(&proc_address);
-            ffi::egl::QueryWaylandBufferWL::load_with(&proc_address);
-        });
 
         // the first step is to query the list of extensions without any display, if supported
         let dp_extensions = unsafe {
@@ -112,9 +91,17 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
         debug!(log, "EGL No-Display Extensions: {:?}", dp_extensions);
 
         let display = unsafe {
-            B::get_display(ptr, |e: &str| dp_extensions.iter().any(|s| s == e), log.clone())
+            B::get_display(
-                .map_err(Error::DisplayNotSupported)?
+                ptr,
+                &egl_attribs,
+                |e: &str| dp_extensions.iter().any(|s| s == e),
+                log.clone(),
+            )
+            .map_err(Error::DisplayCreationError)?
         };
+        if display == ffi::egl::NO_DISPLAY {
+            return Err(Error::DisplayNotSupported);
+        }
 
         let egl_version = {
             let mut major: MaybeUninit<ffi::egl::types::EGLint> = MaybeUninit::uninit();
@@ -174,6 +161,7 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
     ) -> Result<(PixelFormat, ffi::egl::types::EGLConfig), Error> {
         let descriptor = {
             let mut out: Vec<c_int> = Vec::with_capacity(37);
+            let surface_type = self.native.borrow().surface_type();
 
             if self.egl_version >= (1, 2) {
                 trace!(self.logger, "Setting COLOR_BUFFER_TYPE to RGB_BUFFER");
@@ -181,12 +169,12 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
                 out.push(ffi::egl::RGB_BUFFER as c_int);
             }
 
-            trace!(self.logger, "Setting SURFACE_TYPE to WINDOW");
+            trace!(self.logger, "Setting SURFACE_TYPE to {}", surface_type);
 
             out.push(ffi::egl::SURFACE_TYPE as c_int);
             // TODO: Some versions of Mesa report a BAD_ATTRIBUTE error
             // if we ask for PBUFFER_BIT as well as WINDOW_BIT
-            out.push((ffi::egl::WINDOW_BIT) as c_int);
+            out.push(surface_type);
 
             match attributes.version {
                 Some((3, _)) => {
@@ -265,11 +253,17 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
             config_ids.set_len(num_configs as usize);
         }
 
-        // TODO: Deeper swap intervals might have some uses
+        if config_ids.is_empty() {
+            return Err(Error::NoAvailablePixelFormat);
+        }
+
         let desired_swap_interval = if attributes.vsync { 1 } else { 0 };
 
-        let config_ids = config_ids
+        // try to select a config with the desired_swap_interval
-            .into_iter()
+        // (but don't fail, as the margin might be very small on some cards and most configs are fine)
+        let config_id = config_ids
+            .iter()
+            .copied()
             .map(|config| unsafe {
                 let mut min_swap_interval = 0;
                 wrap_egl_call(|| {
@@ -305,14 +299,8 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
             .map_err(Error::ConfigFailed)?
             .into_iter()
             .flatten()
-            .collect::<Vec<_>>();
+            .next()
-
+            .unwrap_or_else(|| config_ids[0]);
-        if config_ids.is_empty() {
-            return Err(Error::NoAvailablePixelFormat);
-        }
-
-        // TODO: Improve config selection
-        let config_id = config_ids[0];
 
         // analyzing each config
         macro_rules! attrib {
@@ -371,7 +359,7 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
         double_buffer: Option<bool>,
         config: ffi::egl::types::EGLConfig,
         args: N::Arguments,
-    ) -> Result<EGLSurface<B::Surface>, SurfaceCreationError<N::Error>> {
+    ) -> Result<EGLSurface<B::Surface>, SurfaceCreationError<B::Error>> {
         trace!(self.logger, "Creating EGL window surface.");
         let surface = self
             .native
@@ -391,7 +379,6 @@ impl<B: native::Backend, N: native::NativeDisplay<B>> EGLDisplay<B, N> {
             debug!(self.logger, "EGL surface successfully created");
             x
         })
-        .map_err(SurfaceCreationError::EGLSurfaceCreationFailed)
     }
 
     /// Returns the runtime egl version of this display

src/backend/egl/error.rs

@@ -15,9 +15,12 @@ pub enum Error {
     /// Backend does not match the context type
     #[error("The expected backend '{0:?}' does not match the runtime")]
     NonMatchingBackend(&'static str),
+    /// Display creation failed
+    #[error("Display creation failed with error: {0:}")]
+    DisplayCreationError(#[source] EGLError),
     /// Unable to obtain a valid EGL Display
-    #[error("Unable to obtain a valid EGL Display. Err: {0:}")]
+    #[error("Unable to obtain a valid EGL Display.")]
-    DisplayNotSupported(#[source] EGLError),
+    DisplayNotSupported,
     /// `eglInitialize` returned an error
     #[error("Failed to initialize EGL. Err: {0:}")]
     InitFailed(#[source] EGLError),
@@ -88,6 +91,10 @@ pub enum EGLError {
     /// A NativeWindowType argument does not refer to a valid native window.
     #[error("A NativeWindowType argument does not refer to a valid native window.")]
     BadNativeWindow,
+    #[cfg(feature = "backend_drm_eglstream")]
+    /// The EGL operation failed due to temporary unavailability of a requested resource, but the arguments were otherwise valid, and a subsequent attempt may succeed.
+    #[error("The EGL operation failed due to temporary unavailability of a requested resource, but the arguments were otherwise valid, and a subsequent attempt may succeed.")]
+    ResourceBusy,
     /// A power management event has occurred. The application must destroy all contexts and reinitialise OpenGL ES state and objects to continue rendering.
     #[error("A power management event has occurred. The application must destroy all contexts and reinitialise OpenGL ES state and objects to continue rendering.")]
     ContextLost,
@@ -111,6 +118,8 @@ impl From<u32> for EGLError {
             ffi::egl::BAD_PARAMETER => EGLError::BadParameter,
             ffi::egl::BAD_NATIVE_PIXMAP => EGLError::BadNativePixmap,
             ffi::egl::BAD_NATIVE_WINDOW => EGLError::BadNativeWindow,
+            #[cfg(feature = "backend_drm_eglstream")]
+            ffi::egl::RESOURCE_BUSY_EXT => EGLError::ResourceBusy,
             ffi::egl::CONTEXT_LOST => EGLError::ContextLost,
             x => EGLError::Unknown(x),
         }

src/backend/egl/ffi.rs

@@ -13,6 +13,35 @@ pub type NativeDisplayType = *const c_void;
 pub type NativePixmapType = *const c_void;
 pub type NativeWindowType = *const c_void;
 
+pub fn make_sure_egl_is_loaded() {
+    use std::{ffi::CString, ptr};
+
+    egl::LOAD.call_once(|| unsafe {
+        fn constrain<F>(f: F) -> F
+        where
+            F: for<'a> Fn(&'a str) -> *const ::std::os::raw::c_void,
+        {
+            f
+        };
+
+        egl::load_with(|sym| {
+            let name = CString::new(sym).unwrap();
+            let symbol = egl::LIB.get::<*mut c_void>(name.as_bytes());
+            match symbol {
+                Ok(x) => *x as *const _,
+                Err(_) => ptr::null(),
+            }
+        });
+        let proc_address = constrain(|sym| super::get_proc_address(sym));
+        egl::load_with(&proc_address);
+        egl::BindWaylandDisplayWL::load_with(&proc_address);
+        egl::UnbindWaylandDisplayWL::load_with(&proc_address);
+        egl::QueryWaylandBufferWL::load_with(&proc_address);
+        #[cfg(feature = "backend_drm_eglstream")]
+        egl::StreamConsumerAcquireAttribNV::load_with(&proc_address);
+    });
+}
+
 #[allow(clippy::all, rust_2018_idioms)]
 pub mod egl {
     use super::*;
@@ -169,4 +198,66 @@ pub mod egl {
     // Accepted in the <attribute> parameter of eglQueryWaylandBufferWL:
     pub const EGL_TEXTURE_FORMAT: i32 = 0x3080;
     pub const WAYLAND_Y_INVERTED_WL: i32 = 0x31DB;
+
+    /// nVidia support needs some implemented but only proposed egl extensions...
+    /// Therefor gl_generator cannot generate them and we need some constants...
+    /// And a function...
+    #[cfg(feature = "backend_drm_eglstream")]
+    pub const CONSUMER_AUTO_ACQUIRE_EXT: i32 = 0x332B;
+    #[cfg(feature = "backend_drm_eglstream")]
+    pub const DRM_FLIP_EVENT_DATA_NV: i32 = 0x333E;
+    #[cfg(feature = "backend_drm_eglstream")]
+    pub const CONSUMER_ACQUIRE_TIMEOUT_USEC_KHR: i32 = 0x321E;
+    #[cfg(feature = "backend_drm_eglstream")]
+    pub const RESOURCE_BUSY_EXT: u32 = 0x3353;
+
+    #[cfg(feature = "backend_drm_eglstream")]
+    #[allow(non_snake_case, unused_variables, dead_code)]
+    #[inline]
+    pub unsafe fn StreamConsumerAcquireAttribNV(
+        dpy: types::EGLDisplay,
+        stream: types::EGLStreamKHR,
+        attrib_list: *const types::EGLAttrib,
+    ) -> types::EGLBoolean {
+        __gl_imports::mem::transmute::<
+            _,
+            extern "system" fn(
+                types::EGLDisplay,
+                types::EGLStreamKHR,
+                *const types::EGLAttrib,
+            ) -> types::EGLBoolean,
+        >(nvidia_storage::StreamConsumerAcquireAttribNV.f)(dpy, stream, attrib_list)
+    }
+
+    #[cfg(feature = "backend_drm_eglstream")]
+    mod nvidia_storage {
+        use super::{FnPtr, __gl_imports::raw};
+        pub static mut StreamConsumerAcquireAttribNV: FnPtr = FnPtr {
+            f: super::missing_fn_panic as *const raw::c_void,
+            is_loaded: false,
+        };
+    }
+
+    #[cfg(feature = "backend_drm_eglstream")]
+    #[allow(non_snake_case)]
+    pub mod StreamConsumerAcquireAttribNV {
+        use super::{FnPtr, __gl_imports::raw, metaloadfn, nvidia_storage};
+
+        #[inline]
+        #[allow(dead_code)]
+        pub fn is_loaded() -> bool {
+            unsafe { nvidia_storage::StreamConsumerAcquireAttribNV.is_loaded }
+        }
+
+        #[allow(dead_code)]
+        pub fn load_with<F>(mut loadfn: F)
+        where
+            F: FnMut(&str) -> *const raw::c_void,
+        {
+            unsafe {
+                nvidia_storage::StreamConsumerAcquireAttribNV =
+                    FnPtr::new(metaloadfn(&mut loadfn, "eglStreamConsumerAcquireAttribNV", &[]))
+            }
+        }
+    }
 }

src/backend/egl/native.rs

@@ -1,9 +1,10 @@
 //! Type safe native types for safe context/surface creation
 
-use super::{ffi, wrap_egl_call, EGLError, Error};
+use super::{
-
+    display::EGLDisplayHandle, ffi, wrap_egl_call, EGLError, Error, SurfaceCreationError, SwapBuffersError,
-#[cfg(feature = "backend_winit")]
+};
-use std::ptr;
+use nix::libc::{c_int, c_void};
+use std::sync::Arc;
 
 #[cfg(feature = "backend_winit")]
 use wayland_egl as wegl;
@@ -15,7 +16,9 @@ use winit::window::Window as WinitWindow;
 /// Trait for typed backend variants (X11/Wayland/GBM)
 pub trait Backend {
     /// Surface type created by this backend
-    type Surface: NativeSurface;
+    type Surface: NativeSurface<Error = Self::Error>;
+    /// Error type thrown by the surface creation in case of failure.
+    type Error: ::std::error::Error + Send + 'static;
 
     /// Return an [`EGLDisplay`](ffi::egl::types::EGLDisplay) based on this backend
     ///
@@ -25,6 +28,7 @@ pub trait Backend {
     /// but there is no way to test that.
     unsafe fn get_display<F: Fn(&str) -> bool>(
         display: ffi::NativeDisplayType,
+        attribs: &[ffi::EGLint],
         has_dp_extension: F,
         log: ::slog::Logger,
     ) -> Result<ffi::egl::types::EGLDisplay, EGLError>;
@@ -36,9 +40,11 @@ pub enum Wayland {}
 #[cfg(feature = "backend_winit")]
 impl Backend for Wayland {
     type Surface = wegl::WlEglSurface;
+    type Error = Error;
 
     unsafe fn get_display<F>(
         display: ffi::NativeDisplayType,
+        attribs: &[ffi::EGLint],
         has_dp_extension: F,
         log: ::slog::Logger,
     ) -> Result<ffi::egl::types::EGLDisplay, EGLError>
@@ -47,8 +53,13 @@ impl Backend for Wayland {
     {
         if has_dp_extension("EGL_KHR_platform_wayland") && ffi::egl::GetPlatformDisplay::is_loaded() {
             trace!(log, "EGL Display Initialization via EGL_KHR_platform_wayland");
+            let attribs = attribs.iter().map(|x| *x as isize).collect::<Vec<_>>();
             wrap_egl_call(|| {
-                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_WAYLAND_KHR, display as *mut _, ptr::null())
+                ffi::egl::GetPlatformDisplay(
+                    ffi::egl::PLATFORM_WAYLAND_KHR,
+                    display as *mut _,
+                    attribs.as_ptr(),
+                )
             })
         } else if has_dp_extension("EGL_EXT_platform_wayland") && ffi::egl::GetPlatformDisplayEXT::is_loaded()
         {
@@ -57,7 +68,7 @@ impl Backend for Wayland {
                 ffi::egl::GetPlatformDisplayEXT(
                     ffi::egl::PLATFORM_WAYLAND_EXT,
                     display as *mut _,
-                    ptr::null(),
+                    attribs.as_ptr(),
                 )
             })
         } else {
@@ -76,9 +87,11 @@ pub enum X11 {}
 #[cfg(feature = "backend_winit")]
 impl Backend for X11 {
     type Surface = XlibWindow;
+    type Error = Error;
 
     unsafe fn get_display<F>(
         display: ffi::NativeDisplayType,
+        attribs: &[ffi::EGLint],
         has_dp_extension: F,
         log: ::slog::Logger,
     ) -> Result<ffi::egl::types::EGLDisplay, EGLError>
@@ -87,13 +100,18 @@ impl Backend for X11 {
     {
         if has_dp_extension("EGL_KHR_platform_x11") && ffi::egl::GetPlatformDisplay::is_loaded() {
             trace!(log, "EGL Display Initialization via EGL_KHR_platform_x11");
+            let attribs = attribs.iter().map(|x| *x as isize).collect::<Vec<_>>();
             wrap_egl_call(|| {
-                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_X11_KHR, display as *mut _, ptr::null())
+                ffi::egl::GetPlatformDisplay(ffi::egl::PLATFORM_X11_KHR, display as *mut _, attribs.as_ptr())
             })
         } else if has_dp_extension("EGL_EXT_platform_x11") && ffi::egl::GetPlatformDisplayEXT::is_loaded() {
             trace!(log, "EGL Display Initialization via EGL_EXT_platform_x11");
             wrap_egl_call(|| {
-                ffi::egl::GetPlatformDisplayEXT(ffi::egl::PLATFORM_X11_EXT, display as *mut _, ptr::null())
+                ffi::egl::GetPlatformDisplayEXT(
+                    ffi::egl::PLATFORM_X11_EXT,
+                    display as *mut _,
+                    attribs.as_ptr(),
+                )
             })
         } else {
             trace!(log, "Default EGL Display Initialization via GetDisplay");
@@ -110,21 +128,28 @@ impl Backend for X11 {
 pub unsafe trait NativeDisplay<B: Backend> {
     /// Arguments used to surface creation.
     type Arguments;
-    /// Error type thrown by the surface creation in case of failure.
-    type Error: ::std::error::Error + Send + 'static;
     /// Because one type might implement multiple [`Backend`]s this function must be called to check
     /// if the expected [`Backend`] is used at runtime.
     fn is_backend(&self) -> bool;
     /// Return a raw pointer EGL will accept for context creation.
     fn ptr(&self) -> Result<ffi::NativeDisplayType, Error>;
+    /// Return attributes that might be used by `B::get_display`
+    ///
+    /// Default implementation returns an empty list
+    fn attributes(&self) -> Vec<ffi::EGLint> {
+        vec![ffi::egl::NONE as ffi::EGLint]
+    }
+    /// Type of surfaces created
+    fn surface_type(&self) -> ffi::EGLint {
+        ffi::egl::WINDOW_BIT as ffi::EGLint
+    }
     /// Create a surface
-    fn create_surface(&mut self, args: Self::Arguments) -> Result<B::Surface, Self::Error>;
+    fn create_surface(&mut self, args: Self::Arguments) -> Result<B::Surface, B::Error>;
 }
 
 #[cfg(feature = "backend_winit")]
 unsafe impl NativeDisplay<X11> for WinitWindow {
     type Arguments = ();
-    type Error = Error;
 
     fn is_backend(&self) -> bool {
         self.xlib_display().is_some()
@@ -146,7 +171,6 @@ unsafe impl NativeDisplay<X11> for WinitWindow {
 #[cfg(feature = "backend_winit")]
 unsafe impl NativeDisplay<Wayland> for WinitWindow {
     type Arguments = ();
-    type Error = Error;
 
     fn is_backend(&self) -> bool {
         self.wayland_display().is_some()
@@ -177,67 +201,88 @@ unsafe impl NativeDisplay<Wayland> for WinitWindow {
 /// The returned [`NativeWindowType`](ffi::NativeWindowType) must be valid for EGL
 /// and there is no way to test that.
 pub unsafe trait NativeSurface {
-    /// Error of the underlying surface
+    /// Error type thrown by the surface creation in case of failure.
-    type Error: std::error::Error;
+    type Error: ::std::error::Error + Send + 'static;
-
+    /// Create an EGLSurface from the internal native type.
-    /// Return a raw pointer egl will accept for surface creation.
+    ///
-    fn ptr(&self) -> ffi::NativeWindowType;
+    /// Must be able to deal with re-creation of existing resources,
+    /// if `needs_recreation` can return `true`.
+    ///
+    /// # Safety
+    /// This is usually an unsafe operation returning a raw pointer.
+    unsafe fn create(
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attributes: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Self::Error>>;
 
     /// Will be called to check if any internal resources will need
-    /// to be recreated. Old resources must be used until `recreate`
+    /// to be recreated. Old resources must be used until `create`
-    /// was called.
+    /// was called again and a new surface was optained.
     ///
-    /// Only needs to be recreated, if this shall sometimes return true.
+    /// Only needs to be recreated, if this may return true.
     /// The default implementation always returns false.
     fn needs_recreation(&self) -> bool {
         false
     }
 
-    /// Instructs the surface to recreate internal resources
-    ///
-    /// Must only be implemented if `needs_recreation` can return `true`.
-    /// Returns true on success.
-    /// If this call was successful `ptr()` *should* return something different.
-    fn recreate(&self) -> Result<(), Self::Error> {
-        Ok(())
-    }
-
     /// Adds additional semantics when calling
     /// [EGLSurface::swap_buffers](::backend::egl::surface::EGLSurface::swap_buffers)
     ///
     /// Only implement if required by the backend.
-    fn swap_buffers(&self) -> Result<(), Self::Error> {
+    fn swap_buffers(
-        Ok(())
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        surface: ffi::egl::types::EGLSurface,
+    ) -> Result<(), SwapBuffersError<Self::Error>> {
+        wrap_egl_call(|| unsafe {
+            ffi::egl::SwapBuffers(***display, surface as *const _);
+        })
+        .map_err(SwapBuffersError::EGLSwapBuffers)
     }
 }
 
-/// Hack until ! gets stablized
-#[derive(Debug)]
-pub enum Never {}
-impl std::fmt::Display for Never {
-    fn fmt(&self, _f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        unreachable!()
-    }
-}
-impl std::error::Error for Never {}
-
 #[cfg(feature = "backend_winit")]
 unsafe impl NativeSurface for XlibWindow {
-    // this would really be a case for this:
+    type Error = Error;
-    // type Error = !; (https://github.com/rust-lang/rust/issues/35121)
-    type Error = Never;
 
-    fn ptr(&self) -> ffi::NativeWindowType {
+    unsafe fn create(
-        self.0 as *const _
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attributes: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Error>> {
+        wrap_egl_call(|| {
+            ffi::egl::CreateWindowSurface(
+                display.handle,
+                config_id,
+                self.0 as *const _,
+                surface_attributes.as_ptr(),
+            )
+        })
+        .map_err(SurfaceCreationError::EGLSurfaceCreationFailed)
     }
 }
 
 #[cfg(feature = "backend_winit")]
 unsafe impl NativeSurface for wegl::WlEglSurface {
-    // type Error = !;
+    type Error = Error;
-    type Error = Never;
 
-    fn ptr(&self) -> ffi::NativeWindowType {
+    unsafe fn create(
-        self.ptr() as *const _
+        &self,
+        display: &Arc<EGLDisplayHandle>,
+        config_id: ffi::egl::types::EGLConfig,
+        surface_attributes: &[c_int],
+    ) -> Result<*const c_void, SurfaceCreationError<Error>> {
+        wrap_egl_call(|| {
+            ffi::egl::CreateWindowSurface(
+                display.handle,
+                config_id,
+                self.ptr() as *const _,
+                surface_attributes.as_ptr(),
+            )
+        })
+        .map_err(SurfaceCreationError::EGLSurfaceCreationFailed)
     }
 }

src/backend/egl/surface.rs

@@ -1,6 +1,6 @@
 //! EGL surface related structs
 
-use super::{ffi, native, wrap_egl_call, EGLError, SwapBuffersError};
+use super::{ffi, native, EGLError, SurfaceCreationError, SwapBuffersError};
 use crate::backend::egl::display::EGLDisplayHandle;
 use crate::backend::graphics::PixelFormat;
 use nix::libc::c_int;
@@ -42,7 +42,7 @@ impl<N: native::NativeSurface> EGLSurface<N> {
         config: ffi::egl::types::EGLConfig,
         native: N,
         log: L,
-    ) -> Result<EGLSurface<N>, EGLError>
+    ) -> Result<EGLSurface<N>, SurfaceCreationError<N::Error>>
     where
         L: Into<Option<::slog::Logger>>,
     {
@@ -69,12 +69,12 @@ impl<N: native::NativeSurface> EGLSurface<N> {
             out
         };
 
-        let surface = wrap_egl_call(|| unsafe {
+        let surface = unsafe { native.create(&display, config, &surface_attributes)? };
-            ffi::egl::CreateWindowSurface(**display, config, native.ptr(), surface_attributes.as_ptr())
-        })?;
 
         if surface == ffi::egl::NO_SURFACE {
-            return Err(EGLError::BadSurface);
+            return Err(SurfaceCreationError::EGLSurfaceCreationFailed(
+                EGLError::BadSurface,
+            ));
         }
 
         Ok(EGLSurface {
@@ -93,9 +93,7 @@ impl<N: native::NativeSurface> EGLSurface<N> {
         let surface = self.surface.get();
 
         let result = if !surface.is_null() {
-            wrap_egl_call(|| unsafe { ffi::egl::SwapBuffers(**self.display, surface as *const _) })
+            self.native.swap_buffers(&self.display, surface)
-                .map_err(SwapBuffersError::EGLSwapBuffers)
-                .and_then(|_| self.native.swap_buffers().map_err(SwapBuffersError::Underlying))
         } else {
             Err(SwapBuffersError::EGLSwapBuffers(EGLError::BadSurface))
         };
@@ -108,20 +106,20 @@ impl<N: native::NativeSurface> EGLSurface<N> {
         };
 
         if self.native.needs_recreation() || surface.is_null() || is_bad_surface {
-            self.native.recreate().map_err(SwapBuffersError::Underlying)?;
             if !surface.is_null() {
                 let _ = unsafe { ffi::egl::DestroySurface(**self.display, surface as *const _) };
             }
             self.surface.set(unsafe {
-                wrap_egl_call(|| {
+                self.native
-                    ffi::egl::CreateWindowSurface(
+                    .create(&self.display, self.config_id, &self.surface_attributes)
-                        **self.display,
+                    .map_err(|err| match err {
-                        self.config_id,
+                        SurfaceCreationError::EGLSurfaceCreationFailed(err) => {
-                        self.native.ptr(),
+                            SwapBuffersError::EGLCreateWindowSurface(err)
-                        self.surface_attributes.as_ptr(),
+                        }
-                    )
+                        SurfaceCreationError::NativeSurfaceCreationFailed(err) => {
-                })
+                            SwapBuffersError::Underlying(err)
-                .map_err(SwapBuffersError::EGLCreateWindowSurface)?
+                        }
+                    })?
             });
 
             result.map_err(|err| {

src/backend/graphics/mod.rs

@@ -32,7 +32,7 @@ pub enum SwapBuffersError {
     ///
     /// Operations will have no effect. Functions that read textures, buffers, etc.
     /// will return uninitialized data instead.
-    #[error("The context has been lost, it needs to be recreated")]
+    #[error("The context has been lost, it needs to be recreated: {0}")]
     ContextLost(Box<dyn std::error::Error>),
     /// A temporary condition caused to rendering to fail.
     ///
@@ -43,6 +43,6 @@ pub enum SwapBuffersError {
     /// Proceed after investigating the source to reschedule another full rendering step or just this page_flip at a later time.
     /// If the root cause cannot be discovered and subsequent renderings also fail, it is advised to fallback to
     /// recreation.
-    #[error("A temporary condition caused the page flip to fail.")]
+    #[error("A temporary condition caused the page flip to fail: {0}")]
     TemporaryFailure(Box<dyn std::error::Error>),
 }

src/backend/udev.rs

@@ -256,3 +256,24 @@ pub fn all_gpus<S: AsRef<str>>(seat: S) -> IoResult<Vec<PathBuf>> {
         .flat_map(|device| device.devnode().map(PathBuf::from))
         .collect())
 }
+
+/// Returns the loaded driver for a device named by it's [`dev_t`](::nix::sys::stat::dev_t).
+pub fn driver(dev: dev_t) -> IoResult<Option<OsString>> {
+    let mut enumerator = Enumerator::new()?;
+    enumerator.match_subsystem("drm")?;
+    enumerator.match_sysname("card[0-9]*")?;
+    Ok(enumerator
+        .scan_devices()?
+        .filter(|device| device.devnum() == Some(dev))
+        .flat_map(|dev| {
+            let mut device = Some(dev);
+            while let Some(dev) = device {
+                if dev.driver().is_some() {
+                    return dev.driver().map(std::ffi::OsStr::to_os_string);
+                }
+                device = dev.parent();
+            }
+            None
+        })
+        .next())
+}