Bug 520361

Summary:	Connecting monitor through DisplayLink dock crashes KWin
Product:	[Plasma] kwin	Reporter:	Noah Davis <noahadvs>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	crash	CC:	matthijsbulsink, nate
Priority:	NOR
Version First Reported In:	git master
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=521668
Latest Commit:	https://invent.kde.org/plasma/kwin/-/commit/0d6b757c011333469806e662f077a94c3033fbeb	Version Fixed/Implemented In:	6.7.1
Sentry Crash Report:
Attachments:	kwin_wayland all threads backtrace from GDB attached via SSH

Description Noah Davis 2026-05-18 20:21:38 UTC

Created attachment 192427 [details]
kwin_wayland all threads backtrace from GDB attached via SSH

DESCRIPTION
When I connect my InnoView INVPM003 portable monitor (https://www.amazon.com/dp/B0CZ8JZWPX) through my Minisopuru MD6950U DisplayLink dock (https://minisopuru.com/products/md6950u), KWin Wayland 6.7.80 (kde-builder) crashes, every time. The crash does not happen with KWin X11 6.7.80 (kde-builder) or KWin Wayland 6.6.5 (root system).

I have attached a GDB backtrace. There are some unknown symbols in the backtrace where llvmpipe is mentioned, but I have installed all the debuginfo packages that could be installed.

STEPS TO REPRODUCE
1. Turn on DisplayLink dock after the InnoView monitor is connected to the dock and the dock is connected to my laptop via USB C port.
2. Wait for KWin to use the InnoView monitor.

OBSERVED RESULT
KWin crashes repeatedly until I turn off the DisplayLink dock. KWin stops trying to restart if I wait long enough.

EXPECTED RESULT
KWin doesn't crash.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20260516
KDE Plasma Version: 6.7.80
KDE Frameworks Version: 6.27.0
Qt Version: 6.11.0
Kernel Version: 7.0.7-1-default (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 4800H with Radeon Graphics
Memory: 32 GiB of RAM (30.8 GiB usable)
Graphics Processor: AMD Radeon Graphics
Manufacturer: Eluktronics
Product Name: THINN-15

Comment 1 Bug Janitor Service 2026-05-18 20:49:27 UTC

A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/9236

Comment 2 Zamundaaa 2026-05-19 10:33:32 UTC

Git commit d70f8843dc2b670f473514b3e23629529054ae32 by Xaver Hugl.
Committed on 19/05/2026 at 10:08.
Pushed by zamundaaa into branch 'master'.

backends/drm: don't use a software renderer for multi GPU copies

The existing code was intended to do this for performance reasons, but since a
render device is created for software rendering, it didn't work.

M  +1    -1    src/backends/drm/drm_egl_layer_surface.cpp

https://invent.kde.org/plasma/kwin/-/commit/d70f8843dc2b670f473514b3e23629529054ae32

Comment 3 Zamundaaa 2026-05-19 11:34:50 UTC

Git commit 0d6b757c011333469806e662f077a94c3033fbeb by Xaver Hugl.
Committed on 19/05/2026 at 11:12.
Pushed by zamundaaa into branch 'Plasma/6.7'.

backends/drm: don't use a software renderer for multi GPU copies

The existing code was intended to do this for performance reasons, but since a
render device is created for software rendering, it didn't work.


(cherry picked from commit d70f8843dc2b670f473514b3e23629529054ae32)

Co-authored-by: Xaver Hugl <xaver.hugl@kde.org>

M  +1    -1    src/backends/drm/drm_egl_layer_surface.cpp

https://invent.kde.org/plasma/kwin/-/commit/0d6b757c011333469806e662f077a94c3033fbeb

Comment 4 matthijsbulsink@hotmail.com 2026-06-20 10:37:32 UTC


*** This bug has been marked as a duplicate of bug 521668 ***