Bug 485154

Summary:	KWin under Wayland can't output through a Lenovo 40AY dock with a Lenovo P14S
Product:	[Plasma] kwin	Reporter:	Freyja Domville <freyjadomville>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	xaver.hugl
Priority:	NOR
Version First Reported In:	6.0.3
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Freyja Domville 2024-04-06 21:47:56 UTC

SUMMARY
If I log in through SDDM on Arch Linux with KDE 6.0.3, kernel 6.8, mesa 24.1, I get a black screen on the display outputs under Wayland with an amdgpu Lenovo P14s (Gen 2 AMD). XOrg works fine.

STEPS TO REPRODUCE
1. Connect the laptop to the dock
2. Log in with Wayland

OBSERVED RESULT
Black screens in the display outputs which were seen working under SDDM XOrg (and KWin with XOrg)

EXPECTED RESULT
Screens show up normally

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:
(available in About System)
KDE Plasma Version: 6.0.3 
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.3

ADDITIONAL INFORMATION
Wasn't able to get logs from the machine in the failure case - I switched to another DE because I need something with decent tiling (accessibility issues mean mouse usage needs to be minimised) and polonium only supports Wayland.

Comment 1 Zamundaaa 2024-04-06 22:54:51 UTC

This is https://gitlab.freedesktop.org/drm/amd/-/issues/2598, please mention there that you're affected by it too.
You can use the KWIN_DRM_PREFER_COLOR_DEPTH=24 environment variable as a workaround