Bug 442601 - Sometimes a Xwayland window stops repainting when minimized/unminimized with click on task manager
Summary: Sometimes a Xwayland window stops repainting when minimized/unminimized with ...
Status: RESOLVED WORKSFORME
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (show other bugs)
Version: 5.22.90
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-09-17 14:23 UTC by Patrick Silva
Modified: 2021-10-13 14:11 UTC (History)
1 user (show)

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Latest Commit:
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Description Patrick Silva 2021-09-17 14:23:45 UTC
SUMMARY
I can't reproduce this bug consistently, sometimes it occurs after the steps below.

STEPS TO REPRODUCE
1. use Wayland session
2. play a video with VLC player running on Xwayland
3. minimize and then unminimize VLC by quickly clicking on its entry in task manager

OBSERVED RESULT
Sometimes VLC window stops repainting and apparently the video is paused.
If this bug did not occur after the steps above, repeat the step 3. Probably at some point the bug will occur.
The already open bugged window repaints again if I apply another Lattency setting in Compositor KCM. 

EXPECTED RESULT
the bug reported here should not occur

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.22.90
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Graphics Platform: Wayland

ADDITIONAL INFORMATION
Other affected Xwayland apps: Discord, Opera internet browser and Strawberry player (Qt6).
This bug also occurs on neon unstable.
Comment 1 Vlad Zahorodnii 2021-09-17 14:29:09 UTC
Can't reproduce after a dozen of attempts.
Comment 2 Patrick Silva 2021-09-20 20:38:59 UTC
I was able to reproduce consistently on neon unstable a few minutes ago with the steps below after running Opera browser for ~5 hours. Then I restarted Opera and now I'm no longer able to reproduce.

1. run Opera in a virtual desktop
2. while Opera window is focused and maximized, switch to another virtual
desktop by clicking on Pager widget placed on Plasma panel
3. switch back to virtual desktop where Opera is
4. minimize and then unminimize Opera by clicking on its entry in task manager

Reult: Opera window stopped repainting. When I clicked on any tab, the label of Opera entry in task manager changed according to, but nothing changed in Opera window. Again changing Latency setting in Compositor KCM fixed the bug temporarily.

Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.23.80
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.3
Graphics Platform: Wayland
Comment 3 Vlad Zahorodnii 2021-09-21 07:34:04 UTC
> Opera window stopped repainting
Was it frozen or invisible?
Comment 4 Patrick Silva 2021-09-21 11:25:25 UTC
(In reply to Vlad Zahorodnii from comment #3)
> > Opera window stopped repainting
> Was it frozen or invisible?

Almost always frozen. I got an invisible window just once yesterday (and a visual glich on my wallpaper at the same time), that's why I restarted Opera.

Today I can reproduce consistently with Opera on neon unstable after changing Lattency settings in Compositor KCM.

1. open Opera
2. open Compositor KCM
3. change Lattency setting and apply the change
4. go back to Opera window by clicking on its entry in task manager
5. click or scroll the page in Opera: window reacts as expected
6. minimize and unminimize Opera by clicking on task manager

Result: Opera window is frozen. Scrolling and mouse clicks
have no visual effect.
Comment 5 Nate Graham 2021-09-21 22:42:37 UTC
Cannot reproduce with VLC.
Comment 6 Vlad Zahorodnii 2021-10-13 14:11:08 UTC
I believe this issue should be fixed. There was a bug wrt handling of xwayland windows changing wl_surface objects. If you can reproduce this issue in git master, please reopen this bug report.