Bug 2375328 - KDE screen locking since 6.4.1 results in "The screen locker is broken" screen
Summary: KDE screen locking since 6.4.1 results in "The screen locker is broken" screen
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: kscreenlocker
Version: 41
Hardware: x86_64
OS: Linux
unspecified
urgent
Target Milestone: ---
Assignee: KDE SIG
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-06-28 14:20 UTC by Walter Francis
Modified: 2025-06-30 23:39 UTC (History)
7 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: Bug
Embargoed:


Attachments (Terms of Use)

Description Walter Francis 2025-06-28 14:20:41 UTC
Description of problem:
Upon update to 6.4.1, as far as I can tell, existing and new users as soon as the screen locker kicks in, you get the "The screen locker is broken" screen forcing users to do silly stuff to log back in.

Per a thread I found on Reddit there is a workaround to go into System Settings, Screensaver, Appearance, and set any wallpaper and apply.  As for what's actually causing the issue I do not know.

Version-Release number of selected component (if applicable):
6.4.1

How reproducible:
100% for new installs, new, and existing users

Steps to Reproduce:
1. Update
2. Lock screen
3. Wonder why KDE made this lock screen make you do silly stuff to log back in

Actual results:
Broken screen telling you to go to the console to log back in.

Expected results:
Lock screen works, lets you log back in.  Handles minor exceptions like whatever is causing this.

Additional info:
Stomach acid is strong enough to melt metal

Comment 1 Laurentiu Pancescu 2025-06-28 18:32:46 UTC
I have a mini-PC configured to suspend after 15 minutes. Besides the "unable to lock, use loginctl unlock-session N" issue described by Walter, when the mini-PC wakes up from suspend, the entire KDE Plasma session is gone, including all programs that were running in it, and abrt-applet prompts me to report a crash in each of the running program.

Clicking a wallpaper in System Settings, as described by Walter, solves both the "use loginctl" and the "session dies on suspend" issues for me.

Comment 2 pg_tips 2025-06-28 22:14:44 UTC
qt6-qtwayland 6.9.1-2 seems to be involved here: https://bugzilla.redhat.com/show_bug.cgi?id=2375356

With that reverted to 6.9.1-1, and nothing else reverted (i.e. all Plasma-related packages at their latest version), I don't get this issue at all.

If I reupgrade qt6-qtwayland to 6.9.1-2 again, and don't touch any other packages. the lockscreen issue comes back.

Comment 3 udippel 2025-06-29 13:37:31 UTC
I cannot confirm some here:

1. I had a wallpaper set, and yet was hit by this.
2. After logging in through ssh, and unlock the session, everything was up as of before, luckily. 
3. My workaround is to simply set the screen lock to "Never".

I *think* I could not reach a virtual console, like what was suggested on the black screen. I am not sure, because I was nervous since I had some process running for a few hours and was most keen to not lose it.

Comment 4 pg_tips 2025-06-29 13:44:58 UTC
The "broken screenlocker" screen suggests Ctrl-Alt-F1 for a virtual console, which on most Fedora installs I think won't work. Ctrl-Alt-F3 should work.

Downgrading qt6-qtwayland to 6.9.1-1 should resolve the issue: a couple of methods are suggested in comments at https://bugzilla.redhat.com/show_bug.cgi?id=2375356

btw my own experience was that changing the wallpaper seemed to mitigate the issue for a short time, but until I downgraded qt6-qtwayland, the lockscreen issue kept coming back: I didn't figure out exactly what conditions retriggered it.

Comment 5 pg_tips 2025-06-30 07:15:38 UTC
A related bug https://bugzilla.redhat.com/show_bug.cgi?id=2375438 appears to have been raised against layer-shell-qt. I don't have access to it, but I guess Red Hat folks may.


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