Bug 505516

Summary:	On X11, the Plasma interface (panels, wallpaper, etc) disappears after screen sleep in multi-screen setups
Product:	[Plasma] plasmashell	Reporter:	Riccardo Robecchi <sephiroth_pk>
Component:	Containment	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	kde, kdedev, nate, notmart
Priority:	NOR	Keywords:	multiscreen, X11-only
Version First Reported In:	6.3.5
Target Milestone:	1.0
Platform:	Neon
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=505336
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Riccardo Robecchi 2025-06-12 10:41:23 UTC

SUMMARY
In a multi-screen setup, the whole Plasma interface (so panels, wallpaper, widgets, etc) disappears after the screens go to sleep due to inactivity. Windows are still correctly positioned in their respective screens, but the Plasma interface is gone and only leaves a black background. Maximising a window makes it take up the whole screen, as if there were no panels at all.
This is 100% reproducible on both my laptop and my desktop. Interestingly enough, it does not happen with my laptop connected to a docking station (HP G5), but it does happen when the laptop is connected directly to an external screen. The screens are arranged vertically.

STEPS TO REPRODUCE
1. Let the screen go to sleep
2. ?

OBSERVED RESULT
Plasma loses the configuration of the secondary screen and only shows a black screen. A restart brings back the UI.

EXPECTED RESULT
Plasma does not lose the configuration and no restart is required.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE neon
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.0

ADDITIONAL INFORMATION

Comment 1 Riccardo Robecchi 2025-06-12 10:43:01 UTC

Sorry, I realised I didn't include an important detail. The interface on the primary (e.g. laptop's) screen never goes away, it is only the secondary screen that experiences this.

Comment 2 Nate Graham 2025-06-12 16:13:57 UTC

Do you have an NVIDIA GPU? If so, this is Bug 490040.

If not, it'll be one of the other bug reports tracking this on X11

Comment 3 Riccardo Robecchi 2025-06-12 16:24:02 UTC

Ah, I forgot to include that too. In both cases it's AMD. I tried looking up existing reports, but I couldn't find anything.

Comment 4 Nate Graham 2025-06-13 15:14:10 UTC Comment hidden (spam)

Unfortunately that's a 0 byte file. Can you try it again?

Comment 5 Riccardo Robecchi 2025-06-13 15:15:36 UTC Comment hidden (spam)

(In reply to Nate Graham from comment #4)
> Unfortunately that's a 0 byte file. Can you try it again?

Not sure this reply was meant for this thread. Was I meant to attach any file?

Comment 6 Nate Graham 2025-06-13 15:17:37 UTC Comment hidden (spam)

It was meant for another bug report, sorry.

Comment 7 Nate Graham 2025-06-13 15:17:55 UTC

Actual intended comment for this bug report: does the UI come back if you restart just plasmashell, or switch TTYs? If so, it sounds similar to Bug 496926.

Comment 8 Riccardo Robecchi 2025-06-15 15:23:38 UTC

That's similar, but it doesn't look to be the same. In that case no input is possible, in my case it works without issues. It's as if plasmashell ignored the secondary screen and doesn't draw anything on it, but everything else works correctly (e.g. I can use KRunner to restart plasmashell, windows of applications still respond to any and all input).

Comment 9 TraceyC 2025-07-10 22:08:13 UTC

This sounds similar to bug 505336 in that 
- Windows are still displayed
- Panel / containment is gone leaving a black background

Does the screenshot in that bug look similar to what you're seeing ?

Comment 10 Riccardo Robecchi 2025-07-11 08:27:19 UTC

(In reply to TraceyC from comment #9)
> This sounds similar to bug 505336 in that 
> - Windows are still displayed
> - Panel / containment is gone leaving a black background
> 
> Does the screenshot in that bug look similar to what you're seeing ?

Yes, seemingly with some differences. In that case it looks like the panels are still there, as they still take the space where they are supposed to be, but they are not displayed; in my case, they are simply entirely absent, as if they weren't there - so maximised windows take the full screen with no black bands. Not sure if it's just two manifestations of the same issue.