Bug 475757

Summary: Weird scaling behaviour on integrated screen when changing resolutions (Wayland)
Product: [Plasma] kwin Reporter: Janet Blackquill <uhhadd>
Component: platform-drmAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED UPSTREAM    
Severity: normal CC: nate, xaver.hugl
Priority: NOR Keywords: qt6
Version First Reported In: master   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Janet Blackquill 2023-10-17 18:07:53 UTC 
SUMMARY
When changing the resolution of my laptop's integrated screen, it takes an indeterminate while for the screen to start rescaling to what Kwin is outputting, as if it's waiting for some condition to trigger an update. Sleeping and restoring the system does not trigger this update.

Touch always rescales immediately without any delay.

STEPS TO REPRODUCE
1. Change resolution downwards
2. Notice the new output is stuck in the top of the hardware display without being rescaled
3.  ???
4. Something happens and the system starts scaling output to fit the display

5. Change resolution back upwards
6. Notice only the top left of the output is being output to the hardware display; as if it is still using the scale of the previous resolution
7. ????
8. Something happens and thesystem starts scaling output to fit the display
Comment 1 Janet Blackquill 2023-10-17 18:13:37 UTC 
It seems to always trigger the resizing when the laptop idles the display off, but not when I explicitly sleep it.
Comment 2 Nate Graham 2023-10-20 17:25:34 UTC 
This is with git master as of the day you reported the issue, right?
Comment 3 Zamundaaa 2023-10-20 17:27:37 UTC 
This is almost guaranteed a driver bug, which needs to be reported at https://gitlab.freedesktop.org/drm/intel/-/issues