Uses EGL_MESA_platform_gbm to get an EglDisplay from a gbm_device.
The DrmBackend can provide a DrmBuffer for a gbm_surface and present
it.
Unfortunately buffer age seems to be slightly broken and we still have
artefacts.
Introduces a new (optional) dependency: libdrm.
The DrmBackend currently supports finding the first connected output.
It can create shared memory buffers which are used by SceneQPainter to
do double buffered rendering.
There is still lots to do, the following things are not yet working:
* multiple outputs
* page flip
* OpenGL (through gbm)
* restoring mode setting to start value
As we use epoxy we don't need them any more. KWin compiles, links and
runs just fine without ever trying to find OpenGL or OpenGLES.
BUG: 340170
FIXED-IN: 5.2.0
Libinput is an optional dependency for getting low level input events.
As opening the input devices requires root privs this is rather
pointless in the current state. But there is a small added test app which
can be executed with root privs to demonstrate the functionality. To
properly get input events we need a wrapper like it's used in weston.
So far the following is setup:
* opening devices found by udev
* forwarding keyboard events to InputRedirection
* forwarding pointer button events to InputRedirection
* forwarding pointer axis events to InputRedirection
* signals emitted for pointer motion events
Pointer motion events need some further work as they are provided
as delta events. We need to track that and map them properly.
Also missing are touch events due to me not having a touch screen.
It should be fairly simple to setup the touch events, though.
Also hotplugging of devices is not yet implemented.
