Bug 482626

Summary: On X11, screen locker flickers for 1-2minutes
Product: [Plasma] kwin Reporter: rodolfosilva2
Component: generalAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: major CC: kde, nate, nicolas, oleksandr, vlad.zahorodnii, xaver.hugl
Priority: NOR Keywords: qt6
Version: 6.0.1   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description rodolfosilva2 2024-03-07 01:34:28 UTC
SUMMARY
***
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***

After upgrading my Arch system from plasma 5.27.8-2 to 6.0.1 i am experiencing the problem.
Setup exactly the same as before, so likely the upgrade is the cause.
nothing gets logged in syslog, please advise how to debug this so i can provide more information

STEPS TO REPRODUCE
1. lock screen or wait for timer to lock screen

OBSERVED RESULT
1. screen flickers and for  ~ 1 second content is shown then flickers then content etc
also keyboard backlight goes on and off when screen content is displayed
2. i can enter my password and unlock while it flickers.
after that flickering continues on desktop too.
3. passing some time hitting keys and using the mouse desktop comes back and i can use normal.
EXPECTED RESULT

Unlock system without flickering

SOFTWARE/OS VERSIONS

Operating System: Arch Linux 
KDE Plasma Version: 6.0.1
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.7.8-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i7-6600U CPU @ 2.60GHz
Memory: 15.3 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 520
Manufacturer: LENOVO
System Version: ThinkPad T570


ADDITIONAL INFORMATION

let me know how to get more debug info i can share here
Comment 1 rodolfosilva2 2024-03-07 02:36:16 UTC
The NVIDIA GPU is not used and no NVIDIA kernel module is loaded
Intel iGPU uses i915 kernel module and is loaded in early KMS

Bug reproduced on 2nd system Thinkpad T540p.
Comment 2 rodolfosilva2 2024-03-07 02:39:06 UTC
bug does not appear on Wayland
Comment 3 rodolfosilva2 2024-03-08 11:07:57 UTC
seems like this is related to https://bugs.kde.org/show_bug.cgi?id=481308
Comment 4 Siddhartha 2024-03-08 14:58:29 UTC
I'm getting the same issue on NixOS. Strangely I was not facing the issue when I initially installed Plasma 6, so it might be because of some dependency update that Arch also has.
Comment 5 rodolfosilva2 2024-03-13 16:49:51 UTC

*** This bug has been marked as a duplicate of bug 481308 ***