Bug 428800 - Screen flicker after long screen lock upon resume with Intel GPU without modesetting enabled
Summary: Screen flicker after long screen lock upon resume with Intel GPU without mode...
Status: RESOLVED DOWNSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: general (other bugs)
Version First Reported In: 5.20.2
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-11-07 20:11 UTC by Gianluca Pettinello
Modified: 2021-10-04 13:02 UTC (History)
2 users (show)

See Also:
Latest Commit:
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Sentry Crash Report:


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Description Gianluca Pettinello 2020-11-07 20:11:04 UTC
SUMMARY
After resuming from long screen lock the screen starts to flicker especially at the bottom. Sometimes the flicker disappears after some minutes. The phenomenon is more evident when using Firefox after the screen  unlock

STEPS TO REPRODUCE
1. Wait the screen lock to activate
2. Leave the screen locked for a long period
3. Open firefox and scroll a bit
4. The flicker starts

OBSERVED RESULT
Screen flickering

EXPECTED RESULT
Screen not flickering

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Archlinux
(available in About System)
KDE Plasma Version: 5.20.2 
KDE Frameworks Version: 5.75
Qt Version: 5.15.1

ADDITIONAL INFORMATION
Graphical card Intel Iris Pro 5200
Nomodeset driver
Comment 1 Nate Graham 2021-08-31 18:49:16 UTC
Are you still experiencing this with Plasma 5.22?
Comment 2 Gianluca Pettinello 2021-09-12 19:20:53 UTC
(In reply to Nate Graham from comment #1)
> Are you still experiencing this with Plasma 5.22?

Hello Nate,
sorry for late reply.
No I don't experience flickering any more. I moved to Intel 2D graphics drivers (xf86-video-intel) instead of modesetting and I disable panel self refresh, still when I was in 5.21 series.
If you want I can try to move back to modesetting and see if it flickers again.

Regards
Gianluca
Comment 3 Nate Graham 2021-09-14 17:18:13 UTC
Sure, that would be be great, thanks!
Comment 4 Gianluca Pettinello 2021-09-18 11:05:49 UTC
(In reply to Nate Graham from comment #3)
> Sure, that would be be great, thanks!

Just done, so far no issue, I'm in X11 session
Comment 5 Gianluca Pettinello 2021-10-02 07:38:14 UTC
(In reply to Gianluca Pettinello from comment #4)
> (In reply to Nate Graham from comment #3)
> > Sure, that would be be great, thanks!
> 
> Just done, so far no issue, I'm in X11 session

Hi Nate,
I can confirm that flickering is not present with intel modesetting
You can close the bug
Thanks
Gianluca
Comment 6 Nate Graham 2021-10-04 13:02:21 UTC
Thanks! It's a downstream graphics driver bug I guess. Isn't modesetting used by default now, IIRC? Either way, if you'd like to follow up, the Mesa devs may appreciate a bug report. See https://docs.mesa3d.org/bugs.html.