Bug 491817

Summary:	Monitors with VRR setting to Auto goes black after turn off & on monitor
Product:	[Plasma] kwin	Reporter:	lihmkev
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	xaver.hugl
Priority:	NOR
Version First Reported In:	6.1.4
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description lihmkev 2024-08-17 11:38:31 UTC

SUMMARY
Monitors with VRR setting to Auto/Always goes black after turn off & on monitor

System: 
Display 1: ASUS PA278QV (75Hz max)
Display 2: LG 24GM79G (144Hz max)

Tested in two AMD CPU, Nvidia GPU systems, both are running Nvidia 555.58 dkms driver from main repo. IIRC the bug was present since plasma 6.0, and only can reproduce in wayland session.
1. AMD 7950x, Nvidia 4090
2. AMD 3600, Nvidia 2060 super


STEPS TO REPRODUCE
1. Turn off monitor while system is not suspended
2. Turn on monitor
3. Enter fullscreen while VRR setting is set to Auto (if VRR setting is always, then the monitor will not display anything)

OBSERVED RESULT
Depends on the monitor, the result is slightly different. The ASUS monitor will not display anything (receive no signal and enter sleep), whereas the LG monitor will not display anything until the fullscreen video starts to play, then it will resume display.

EXPECTED RESULT
Monitor displays image

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.10.5
KDE Plasma Version: 6.1.4
KDE Frameworks Version: 6.5.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION
The above issue could be somewhat fixed by turning off VRR, as stated by other user:
https://www.reddit.com/r/kde/comments/1dpcw7g/full_screen_makes_the_screen_black/

Changing to another tty and go back to the original tty will also fix the problem, until the above STEPS TO REPRODUCE is attempted again.

Comment 1 Zamundaaa 2024-08-20 12:13:15 UTC

This is a driver bug, please report this to https://forums.developer.nvidia.com/c/gpu-graphics/linux/148

Comment 2 lihmkev 2024-09-01 04:11:37 UTC

(In reply to Zamundaaa from comment #1)
> This is a driver bug, please report this to
> https://forums.developer.nvidia.com/c/gpu-graphics/linux/148

Thanks for the reply, I will also find time to report to Nvidia's forum after adjusting the format to match theirs. Weird thing is that the computer with 2060 does not seems to have problem anymore recently.
FYI I also tried the same in Gnome with 4090 and VRR enabled but cannot reproduce the behavior.