gbm: Try to re-create resources and commit if restarting the rendering loop fails

src/backend/drm/gbm/session.rs

@@ -56,13 +56,23 @@ impl<
             for (crtc, backend) in backends.borrow().iter() {
                 if let Some(backend) = backend.upgrade() {
                     // restart rendering loop, if it was previously running
-                    if let Some(Err(err)) = backend
+                    if let Some(fb) = backend.current_frame_buffer.get() {
-                        .current_frame_buffer
+                        if let Err(_) = backend.crtc.page_flip(fb) {
-                        .get()
+                            // Try more!
-                        .map(|fb| backend.crtc.page_flip(fb))
+                            if let Err(err) = backend.recreate() {
-                    {
+                                error!(
-                        warn!(self.logger, "Failed to restart rendering loop. Error: {}", err);
+                                    self.logger,
+                                    "Failed to re-create gbm surface, is the device gone?\n\t{}", err
+                                );
                             }
+                            if let Err(err) = unsafe { backend.page_flip() } {
+                                warn!(self.logger, "Failed to restart rendering loop. Error: {}", err);
+                                // TODO bubble this up the user somehow
+                                //      maybe expose a "running" state from a surface?
+                            }
+                        }
+                    }
+
                     // reset cursor
                     {
                         use ::drm::control::Device;

src/backend/drm/gbm/surface.rs

@@ -91,11 +91,15 @@ impl<D: RawDevice + 'static> GbmSurfaceInternal<D> {
     }
 
     pub fn recreate(&self) -> Result<(), Error<<<D as Device>::Surface as Surface>::Error>> {
-        let (w, h) = self.pending_mode().ok_or(Error::NoModeSet)?.size();
+        let (w, h) = self
+            .pending_mode()
+            .or(self.current_mode())
+            .ok_or(Error::NoModeSet)?
+            .size();
 
         // Recreate the surface and the related resources to match the new
         // resolution.
-        debug!(self.logger, "(Re-)Initializing surface for mode: {}:{}", w, h);
+        debug!(self.logger, "(Re-)Initializing surface (with mode: {}:{})", w, h);
         let surface = self
             .dev
             .borrow_mut()