Bug 491891

Summary:	(Wayland, AMD and Intel) External screen has black containment until restarting plasmashell
Product:	[Plasma] plasmashell	Reporter:	zvova7890
Component:	Desktop Containment	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	kde, nate, notmart, oleg.goro
Priority:	NOR	Keywords:	multiscreen
Version:	6.1.4
Target Milestone:	1.0
Platform:	Other
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=491868 https://bugs.kde.org/show_bug.cgi?id=484431 https://bugs.kde.org/show_bug.cgi?id=494262
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description zvova7890 2024-08-19 09:22:44 UTC

SUMMARY
When I'm connecting a type-c "mini dock station" with an HDMI output, plasma does not persist on both screens (the second output is just black) even though the screen is fully functional. I can configure it and move windows there. It's an interesting effect that when the systemsettings are on the internal screen and I set the external output as primary, nothing happens — plasma remains on the internal screen. However, if I move the system settings to the second screen and apply the same setting, plasma jumps to the second screen, and the internal screen goes black (though still functional). I can reproduce this on two notebooks(AMD and Intel), and it seems to be a Wayland-only problem.
I don't know what logs could be useful, let me know if you need anything additional.

STEPS TO REPRODUCE
1. Connect seconds monitor through typec-to-hdmi converter
2. Configure as extended output
3. Try to achieve plasma on both screen

OBSERVED RESULT
Plasma can persist only on the one screen

EXPECTED RESULT
Plasma appears on both screens, with no black second screen

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.1.4
KDE Frameworks Version: 6.4.0
Qt Version: 6.7.2
Kernel Version: 6.10.4-zen2-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5700U with Radeon Graphics
Memory: 13.5 GiB of RAM
Graphics Processor: AMD Radeon Graphics
Manufacturer: LENOVO
Product Name: 82LN
System Version: IdeaPad 5 15ALC05

Comment 1 Nate Graham 2024-08-19 21:50:32 UTC

I use a similar dock/dongle thingy with an HDMI monitor every day, and have never experienced this.

On the external screen, you can move windows to it but the background is all black, right? You can't right-click on it to get a context menu? Is that correct?

If that's the case, does the issue get resolved if you restart plasmashell with `plasmashell --replace` in a terminal window?

If that works, then can you try creating a new panel on the external screen? After that, disconnect the screen or the USB-C dongle and then connect them again to trigger the issue once more.

At this point in time, does the new panel you created become visible on the external screen, even though the background is all black?

Comment 2 Nate Graham 2024-08-19 22:27:17 UTC

Comment 3 zvova7890 2024-08-21 03:05:31 UTC

>> On the external screen, you can move windows to it but the background is all black, right? You can't right-click on it to get a context menu? Is that correct?

Yes, you are absolutely right.

>> If that's the case, does the issue get resolved if you restart plasmashell with `plasmashell --replace` in a terminal window?

Will check this and other steps soon. It's not my permanent configuration, so I need to get to it.

Comment 4 zvova7890 2024-08-21 21:43:52 UTC

Hm... I reinstalled my Qt6 packages, and it seems the problems have been resolved. It was probably due to some experiments I forgot to revert... 
Sorry for the false alarm :(  The bug can be closed