Bug 428800

Summary:	Screen flicker after long screen lock upon resume with Intel GPU without modesetting enabled
Product:	[Plasma] kwin	Reporter:	Gianluca Pettinello <gianluca.pettinello>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DOWNSTREAM
Severity:	normal	CC:	nate, plasma-bugs-null
Priority:	NOR
Version First Reported In:	5.20.2
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

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.