This fixes a misunderstanding of the DRM API. Only a regular commit applies
properties.
Fixes: b16078769e ("test/libdrm_mock: a test-only commit applies properties")
The previous mock library assumed the DRM client would always set all
properties in the atomic request. However, if a previous test-only commit
has set a property, there's no need to set it again.
Accomodate for this in libdrm_mock. This will be useful when we'll skip
setting properties that haven't changed in libliftoff.
References: https://github.com/emersion/libliftoff/issues/37
Compositors need to drive multiple connectors, each with its own vblank timings.
For each device, there's one separate rendering loop per output.
It's not possible to call liftoff_device_apply each time we want to submit a new
frame to one output, because this could touch another's output state, submitting
a new frame there in the process. When the other output will submit a new frame,
it'll get EBUSY (can't submit two frames without waiting for vblank).
Closes: https://github.com/emersion/libliftoff/issues/21
This test continuously updates a layer's FB for some time, and keeps another
layer static. The continously updated layer should be put in a plane.
The test is disabled for now because priorities aren't implemented yet.
