The current mode was set to NULL to abuse it as state variable
persisting DRM suspend/resume, this results resulted in a segfault on
normal DPMS cycle.
This reverts that change and uses the wlr_output enabled variable, which
also persists and makes more sense.
Legacy gamma lut size now uses the new legacy_crtc member of
wlr_drm_crtc. This was Previously doen using old_crtc in
wlr_drm_connector, but since this refers to the crtc that was connected to
the ouput, this could give the wrong result.
On the drm output the wlr_drm_connector structs are reused.
This struct contains the wlr_output struct, which is reused as well.
The old code kept modes/edid and output state persistent over hotplug.
This nulls the relevant strings, reads newer edid data and removes old
modes on unplug.
The backend destroy signal is emitted before the output_remove
signal is. When the destroy signal is emitted listeners remove
their output_remove listener, so the output_remove signal is never
received and listeners have an invalid output pointer.
The correct way to solve this would be to remove the output_remove
signal completely and use the wlr_output.events.destroy signal
instead. This isn't yet possible because wl_signal_emit is unsafe
and listeners cannot be removed in listeners.
The wlr_drm_surface_init function is called (upon others) when the drm
mode is changed.
When the surface was used previously this replaced the gbm_surface, but
did not replace the gbm buffers (front/back).
With this, wlr_drm_surface_get_from never set up the new buffers with
the new glViewport because surf->front existed.
This frees the buffers to get new buffers on the new surface with the
new viewport.