Bug 506423

Summary:	Switching input source on an externally connected monitor sometimes causes primary monitor to freeze
Product:	[Plasma] kwin	Reporter:	Damien <astroturf.statistic176>
Component:	platform-drm	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	kde, xaver.hugl
Priority:	NOR
Version First Reported In:	git-stable-Plasma/6.3
Target Milestone:	---
Platform:	Manjaro
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Here is output of dmesg and journalctl

Description Damien 2025-07-01 08:26:26 UTC

SUMMARY
I have a laptop and two monitors externally connected: one via USB-C to DP and the other HDMI to HDMI. The first monitor I tend to switch the input source on my first monitor so that it switches over to my Xbox and that is fine with no issues as far as my system is concerned. Sometimes though, when I switch the input source back to my Linux system, the primary monitor (the laptop) ends up freezing. This doesn't always happen, and usually when I switch the input source I can interact with my primary monitor just fine. When it's not fine, the primary monitor is frozen. That means: the cursor is frozen in state, and I can't interact with it at all. Oddly enough, the other two externally connected monitors are just fine, and I can use the cursor on those monitors; effectively there's two cursors at this point: one is frozen in state on the primary monitor, and the other I can move. Disconnecting the hdmi/usb-c cables does not work, so I effectively have to do a hard reboot to resolve the issue.

STEPS TO REPRODUCE
1. Have a primary monitor connected to two external monitors
2. Switch input source on one of the monitors
3. Not sure if time-bound, but switching input source back to the Linux can result in primary monitor freezing

OBSERVED RESULT
Primary monitor freezes, cursor is frozen, can't interact with the primary monitor at all. External ones are fine.

EXPECTED RESULT
All monitors should not be frozen and I should be able to interact with them with no issues.

SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
Kernel Version: 6.15.3-1-MANJARO (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 7840HS w/ Radeon 780M Graphics
Memory: 62.0 GiB of RAM
Graphics Processor 1: AMD Radeon RX 7600M XT
Graphics Processor 2: AMD Radeon 780M Graphics
Manufacturer: TUXEDO
Product Name: TUXEDO Sirius 16 Gen1

Mesa: 25.1.4-arch1.1

Comment 1 David Edmundson 2025-07-02 09:28:19 UTC


*** This bug has been marked as a duplicate of bug 506441 ***

Comment 2 Zamundaaa 2025-07-03 16:24:07 UTC

As this is on Wayland, it's somewhat likely to be different from bug 506441.

Comment 3 Zamundaaa 2025-07-03 16:25:17 UTC

When the screen freezes, is there anything out of the ordinary in
> sudo dmesg
or
> journalctl --user-unit plasma-kwin_wayland --boot 0
?

If you disable PSR (set amdgpu.dcdebugmask=0x10 as a kernel argument to do it), does it still happen?

Comment 4 Damien 2025-07-09 15:48:00 UTC

Created attachment 183092 [details]
Here is output of dmesg and journalctl

Comment 5 Bug Janitor Service 2025-07-24 03:46:46 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!

Comment 6 Damien 2025-07-25 13:52:00 UTC

I attached the log a few weeks back but neglected to update the status of the bug report. Please kindly review the logs and get back to me on the prognosis.