Bug 506538

Summary:	On Wayland, desktop on one Displayport monitor of a multi-monitor setup is black/missing after reboot
Product:	[Plasma] kwin	Reporter:	TraceyC <kdedev>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	notmart, xaver.hugl
Priority:	NOR	Keywords:	multiscreen
Version First Reported In:	git master
Target Milestone:	---
Platform:	Solus
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=506259 https://bugs.kde.org/show_bug.cgi?id=494262
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Bug Depends on:
Bug Blocks:	506893

Description TraceyC 2025-07-03 16:18:51 UTC

SUMMARY
After rebooting, one external display gets a signal but remains black. Panels are not moved, and the display is shown as enabled in Display Configuration. The affected screen is connected via Displayport through a USB-C dock

STEPS TO REPRODUCE
1. Reboot (I had performed system updates and rebooted when they were done)

OBSERVED RESULT
One of two external monitors is black

EXPECTED RESULT
All displays show content

SOFTWARE/OS VERSIONS
Operating System: Solus 4.7
KDE Plasma Version: 6.4.80
KDE Frameworks Version: 6.16.0
Qt Version: 6.9.1
Kernel Version: 6.14.11-320.current (64-bit)
Graphics Platform: Wayland
Processors: 16 × 11th Gen Intel® Core™ i7-11800H @ 2.30GHz
Memory: 64 GiB of RAM (62.5 GiB usable)
Graphics Processor 1: Intel® UHD Graphics
Graphics Processor 2: NVIDIA GeForce RTX 3060 Laptop GPU

Laptop 3840 x 2400 @ 150%
2 external monitors 3440 x 1440 @100 % - connected via USB-C dock.
One via Displayport one via HDMI

ADDITIONAL INFORMATION
Unlike bug 494262, this happens immediately after the system boots back up and does not require the displays to sleep or locking the screen

This started happening in the last few days and has persisted through a few builds of git-master workspace

Restarting plasmashell does not restore the display.
To restore it once, I turned HDR off and on after having tried changing resolution
The next time I turned HDR on and off and then changed the resolution and restored it

Comment 1 Zamundaaa 2025-08-22 12:02:04 UTC

Is there anything visible on the display at all, if you move a window or the cursor to it?

Comment 2 TraceyC 2025-08-22 17:13:56 UTC

(In reply to Zamundaaa from comment #1)
> Is there anything visible on the display at all, if you move a window or the
> cursor to it?

I could move a window to it, but the display didn't show the window, or cursor.

I haven't seen this in the last few weeks. The system now has KF 6.18.0, if that matters.
I'll try to reproduce today and add a note if I can reproduce this or not.

Comment 3 TraceyC 2025-08-23 01:25:51 UTC

I'm no longer able to reproduce this on git-master.