Bug 457188

Summary:	240Hz refresh rate not applied after reboot when using Wayland
Product:	[Plasma] kwin	Reporter:	kde-bugs
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	major	CC:	nate, xaver.hugl
Priority:	NOR
Version First Reported In:	5.25.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description kde-bugs 2022-07-27 08:52:58 UTC

SUMMARY
***
Refresh rate not applied after reboot when using Wayland
***


STEPS TO REPRODUCE
1. Make sure the PC is off
2. Boot the PC
3. Select "Wayland Session" in SDDM
4. Log in

OBSERVED RESULT

The primary monitor shows a black screen with the following warning:

"The current input timing is not supported by the monitor display. Please change your input timing to 1920x1080, 240Hz or any other monitor listed timing as per the monitor specifications"

The second monitor works as expected and the refresh rate for both displays is displayed correctly in the settings. Going to the settings and changing the refresh rate of the primary monitor to anything else, or changing it and immediately reverting the change, fixes the issue for the session.

EXPECTED RESULT

No error message and a functional display right after logging in.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma:  NixOS 22.11 (aka NixOS unstable)
(available in About System)
KDE Plasma Version: 5.25.3
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5
Kernel Version: 5.15.56 (64-bit)

HARDWARE

Primary Monitor: DELL S2522HG, 1920x1080, 240Hz
Secondary Monitor: QNIX QX2710LED, 2560x1440, 60Hz

ADDITIONAL INFORMATION

- SDDM is running using X11, as that seems to be the only way for NixOS at the moment
- The issue does not exist for the X11 session
- The issue does not appear, when logging out and back in of the Wayland session

Comment 1 kde-bugs 2022-07-27 09:05:19 UTC

After trying a little further, this issue only applies to the 240Hz option. All other refresh rates I can select (50Hz, 60Hz, 120Hz, 144Hz) work just fine.

Comment 2 Zamundaaa 2022-07-27 10:54:25 UTC

Does putting
KWIN_DRM_PREFER_COLOR_DEPTH=24
into /etc/environment and rebooting change anything?

Comment 3 kde-bugs 2022-07-27 11:09:20 UTC

(In reply to Zamundaaa from comment #2)
> Does putting
> KWIN_DRM_PREFER_COLOR_DEPTH=24
> into /etc/environment and rebooting change anything?

No, trying this setting unfortunately did not change anything.

Comment 4 kde-bugs 2023-04-29 11:37:41 UTC

I am currently running KDE Plasma version 5.27.4 with KDE Frameworks Version 5.105.0 and the issue seems to have been solved since I created the bug report.