[PATCH weston] libweston/compositor-drm: Reset repaint scheduled status when setting DPMS level to off

[Greg V]

> On 7 March 2018 at 17:36, Marius Vlad <marius-cristian.vlad at nxp.com 
> <https://lists.freedesktop.org/mailman/listinfo/wayland-devel>> wrote:
> /
>> /Otherwise when setting dpms level DPMS_ON, 
>> weston_output_schedule_repaint() //will bail out early and never get a chance to wake up the output. ////Arguably this could also be done in drm_set_dpms() when setting 
>> dpms_off_pending //but I figure it better to do it when deferred./
> /
> Thanks, that's a good catch, but I do wonder how it wasn't getting
> tripped up before. In previous releases, we'd call drm_set_dpms() from
> anywhere, which would block on the update completing and then set the
> DPMS level. I wonder if it's because we would receive a flip-done
> event anyway and call weston_output_finish_frame() after the DPMS had
> completed, which would drive us into repaint-idle.
Hi! I think I might have tripped that up before.

Or a different DPMS bug?
Does "wake up the output" here mean DPMS wake, or starting drawing to that output again?

One of my monitors, which is quite slow to wake up (AOC U2879VF) pretty often becomes frozen after waking up from DPMS.
While on the other monitor (an old NEC MultiSync) this problem never happened.
So like I could move the mouse and see the picture change on that monitor, but the first one was still displaying the frozen picture from before going to sleep.

The log lines were:

|[00:42:10.740] queueing pageflip failed: m [00:42:10.740] Couldn't apply 
state for output DP-2|