wlroots/include/backend
Simon Ser cc8bc0db20 backend/drm: stop restoring CRTCs on exit
This is the cause of the spurious "drmHandleEvent failed" messages
at exit. restore_drm_outputs calls handle_drm_event in a loop without
checking whether the FD is readable, so drmHandleEvent ends up with a
short read (0 bytes) and returns an error.

The loop's goal is to wait for all queued page-flip events to complete,
to allow drmModeSetCrtc calls to succeed without EBUSY. The
drmModeSetCrtc calls are supposed to restore whatever KMS state we were
started with. But it's not clear from my PoV that restoring the KMS
state on exit is desirable.

KMS clients are supposed to save and restore the (full) KMS state on VT
switch, but not on exit. Leaving our KMS state on exit avoids unnecessary
modesets and allows flicker-free transitions between clients. See [1]
for more details, and note that with Pekka we've concluded that a new
flag to reset some KMS props to their default value on compositor
start-up is the best way forward. As a side note, Weston doesn't restore
the CRTC by does disable the cursor plane on exit (see
drm_output_deinit_planes, I still think disabling the cursor plane
shouldn't be necessary on exit).

Additionally, restore_drm_outputs only a subset of the KMS state.
Gamma and other atomic properties aren't accounted for. If the previous
KMS client had some outputs disabled, restore_drm_outputs would restore
a garbage mode.

[1]: https://blog.ffwll.ch/2016/01/vt-switching-with-atomic-modeset.html
2021-07-20 15:33:26 +02:00
..
drm backend/drm: stop restoring CRTCs on exit 2021-07-20 15:33:26 +02:00
session backend/session: Remove session_impl 2021-04-14 23:25:07 +02:00
backend.h backend: automatically create allocator 2021-05-21 22:13:54 +02:00
headless.h backend/headless: remove wlr_output_impl.export_dmabuf 2021-07-12 13:29:03 -04:00
libinput.h backend/libinput: send touch frame events 2021-07-08 09:12:17 +02:00
multi.h Rework session handling 2018-09-24 23:35:09 +02:00
noop.h noop: listen to display destroy and destroy the backend 2020-12-31 20:34:36 +01:00
wayland.h move wlr_box from /types to /util 2021-07-06 21:43:17 +02:00
x11.h backend/x11: remove swapchain 2021-06-07 15:42:38 +02:00