Bug 491604

Summary:	VRR breaks after turning monitor off and on again
Product:	[Plasma] kwin	Reporter:	linuxser999 <ginteak>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	nate, xaver.hugl
Priority:	NOR
Version First Reported In:	6.1.4
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description linuxser999 2024-08-12 05:05:45 UTC

***
If you're not sure this is actually a bug, instead post about it at https://discuss.kde.org

If you're reporting a crash, attach a backtrace with debug symbols; see https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***

SUMMARY
I have Benq Ex240 monitor. Arch linux. Nvidia 2080ti with Wayland. Using a DisplayPort cable.

When "adaptive sync" is set to Automatic or On in KDE Display settings, then turning off and on monitor , the VRR functionality is broken and when fullscreening apps / youtube videos, the screen flickers black periodically or for very long periods of time. If I go into Monitor menu, it says VRR is off, but its like Wayland is trying to force it on?

STEPS TO REPRODUCE
1. Turn on Adaptive sync automatic / on
2. Turn off monitor, turn back on
3. Fullscreen a youtube video, application, game, etc

OBSERVED RESULT
Screen flickers black or stays black for long periods of time. Monitor OSD says VRR off.

It can be fixed to work properly again by either quickly switching resolution back and forth, or switching refresh rate back and forth after turning monitor on again.

EXPECTED RESULT
VRR works fine before turning off monitor, no flickering, or black screen. Should be same after turning back on.

SOFTWARE/OS VERSIONS
Windows:
macOS:
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Linux 6.10.3-arch1-2
KDE Plasma Version: Plasma 6.1.4
KDE Frameworks Version: 6.4.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION

Comment 1 Zamundaaa 2024-08-12 18:49:37 UTC

Sounds like the driver isn't activating vrr properly, and you reset that state with a mode change. Please report it at https://forums.developer.nvidia.com/c/gpu-graphics/linux