KDE(X11) lock screen results in a black screen

Whenever the screen gets locked i get a black screen instead. No field for Password, nothing only a black screen and a cursor. However if i blindly enter my password i can login. I checked the journal but there seems to be nothing related to it at all.
I have that on two different EOS Systems and it is happening on both of them. I assume this is some kind of bug? Both systems are updated and it worked fine just a few days ago. Any clue what might be causing that? (Both Systems use AMD in case that matters). It also seems like the screen doesn’t want turn off/sleep because of that issue.

I tried to reproduce on an old intel machine I had laying around, but it appeared to work fine. It was a laptop, so I tried manually locking it via super + L and shutting and opening the lid. It didn’t black screen for me. How is the device being locked? Is it going into hibernation and then trying to resume?

Nope just “locking” via KDE (super then lock screen). It doesn’t happen on my other Nvidia System neither. But on both my AMD Systems (one is using RX 6600 the other RX 7800). No hibernation nor standby used and the screen hasn’t been turn off. Haven’t tested if it happens under Wayland though. I also set back the settings of SDDM to default and tried changing some Lock-Screen Wallpaper (in case that might be the issue) though nothing. Issue still present. I think it started like 2 days ago after i updated. But don’t really know. I remember seeing my lockscreen wallpaper just a few days ago.

It sounds like a KDE/SDDM bug. Something like this, maybe?

Maybe try with a new user. I have an Nvidia machine and an Intel machine, but no AMD unfortunately. I’m also gonna try reproducing the bug report that @petsam linked.

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I tried to reproduce the issue @petsam linked to, but could not reproduce. I switched sddm to using the elaerun theme and it worked fine. Definitely try the new user thing though in order to rule out user configuration. If nothing here helps. Try posting in the kde forums https://discuss.kde.org

I did but so far no solution neither. Though i found out that the “lock screen” and “change user” screens are two different screens. Since changing the User would work fine i’d get a login screen for that. It’s only the “lock screen” that is causing an issue. I don’t know what lock screen EOS acutally uses i always assumed thats SDDM as well? Any clue?

It might be this: https://bugs.kde.org/show_bug.cgi?id=483163
Try using a plasma style other than breeze.

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Wow bro thank you that really is the issue. Kinda annoying since i pretty much hate using “oxygen” instead of breeze (seems to be the only default theme). Though at least that fixes the issue.Thank you again.

Great find. I was having a read through that bug report and it looks like this one is a doozy for the devs. All types of tests are going on to find the culprit for months.

Someone suggested a workaround to switch to a tty and then back and that apparently makes it work again.

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Kinda odd that it is around for such a long time. I keep my system updated yet the issue first came up like a week ago. I mean it’s not that big of a deal since it still works when logging in blindly. Yet it’s not “pretty” to put it that way.

Yeah odd, but sometimes issues like this happened. I find the difficult to fix bugs to be the most interesting. A long time ago there was the infamous “Can’t print on Tuesday” bug. I’m certainly interested in reading what the eventual solution to this problem ends up being.

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