This change fixes modifier selection by delegating this to the allocators
and thus to libgbm, which can ask the driver for an appropriate modifier
for scanout, that results in the best possible performance.
We do not have this information, the order in which modifiers are returned
by EGL has no meaning and this is far better then testing modifiers
non-deterministically at random and choosing the first one, that does
not error out...
- Remove the `Device`, `Surface`, `RawDevice` and `RawSurface` traits.
We are not trying to merge the different responsibilities between...
- Drm-Surfaces: crtcs and planes for displaying buffers
- Gbm-Surfaces: allocating and managing front- and back-buffers
- EGL-Surfaces: Load drawing apis.
..anymore.
- Instead unify the legacy and atomic backends into one `DrmDevice` and
a `DrmSurface`, that under the hood dispatches onto the different modules.
- Do not keep a list of surfaces inside the devices. These are reference-counting
nightmares and a frequent issue due to the read-only nature of `Rc` and `Arc` and
thread-safety related problems.
- Surfaces are mostly doing state-tracking independently of each other
and contain some more helper functions.
- Simplify session code, because we do not need to pass the events
through three layers of devices and surfaces anymore.
- Each surface now represents a plane. Rendering to a plane is just like
any other rendering step, including the Cursor-plane.
(Legacy interfaces only have one to avoid dealing with short-comings of the api).
`DrmDevice` and `UdevBackend` now do not need to be wrapped into `StateToken`s anymore, but can return a separate `SessionObserver` object using the new `AsSessionObserver` trait.
This change was motivated by allowing the `UdevHandle` to obtain a mutable reference to an `EventLoopHandle` to create wayland object, e.g. a `wl_output` object.
Previously this was not possible.
Depends on https://github.com/Smithay/wayland-rs/pull/164