Since I switched to Wayland on Debian11/KDE starting the computer from standby often shows a black screen with the notice that one should use ctrl+alt+f2 and loginctl unlock-session {id} (this text disappears before one can fully read it). Doing so doesn't help (and running ctrl+alt+f7 shows a frozen login-screen) but running pkill -KILL -u {username} does. Edit: now running loginctl unlock-session {id} like described in the error-message and switching back works too.

I'd like to find out why this occurs and prevent it. Which things (logs etc) should I check or test to do so?

I'm aware that Wayland support isn't yet stable in KDE. This question is about how one could do basic troubleshooting, like checking specific logs or a set of common problems.

The message that's shown shortly is:

The screen locker is broken and unlocking is not possible anymore.
In order to unlock switch to a virtual terminal (e.g. Ctrl+Alt+F2), log in and execute the command:

loginctl unlock-session {id}

Afterwards switch back to the running session (Ctrl+Alt+F8).

The journald log has:

org.kde.ActivityManager qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
dbus-daemon [session uid=1000 pid=2859675] Activating service name='org.kde.ksystemstats' requested by ':1.71' (uid=1000 pid=2867777 comm="/usr/bin/plasmashell ")
dbus-daemon [session uid=1000 pid=2859675] Successfully activated service 'org.kde.ksystemstats'
dbus-daemon [session uid=1000 pid=2859675] Activating service name='org.kde.KSplash' requested by ':1.71' (uid=1000 pid=2867777 comm="/usr/bin/plasmashell ")
dbus-daemon [session uid=1000 pid=2859675] Activating service name='org.kde.kdeconnect' requested by ':1.71' (uid=1000 pid=2867777 comm="/usr/bin/plasmashell ")

(KDE's Kdeconnect and Ksystemstats getting started automatically is another problem I'm having - details in the bug reports here. I don't think that this is causing the problem.)

syslog has these entries from after starting:

kernel: Filesystems sync: 0.0.. seconds
kernel: Freezing user space processes ... (elapsed 0.0.. seconds) done.
kernel: OOM killer disabled.
kernel: Freezing remaining freezable tasks ... (elapsed 0.0.. seconds) done.
kernel: printk: Suspending console(s) (use no_console_suspend to debug)
kernel: serial ...: disabled
kernel: parport_pc ...: disabled
kernel: ...: EEE TX LPI TIMER: ...
kernel: sd ..:0:0:0: [sd..] Stopping disk
kernel: pci 0000:..:00.0: BAR ..: no space for [mem size ...]
kernel: pci 0000:..:00.0: BAR ..: failed to assign [mem size ...]

xlsclients shows the hostname of the computer (as well as Firefox).

Edit: I created an issue here (another one about troubleshooting/logs is linked there).

Edit: after running that command and pressing ctrl+alt+F(8 for example) in the login screen a qemu user is shown again, even though I reran this as a workaround to at least hide the user.

Edit: After pressing ctrl+alt+F(8 for example) to show to login screen after logging the user out it shortly shows the error Failed to start LSB: web-based administration interface for Unix systems before loading the login screen. Moreover, since recently, the VeraCrypt-mounted drive isn't showing as mounted in VeraCrypt anymore in the GUI (but it's still mounted). No veracrypt process is running.

Another thing that's happening with these crashes is that the bash-history file is only around 20kB large, everything else got removed (which means every time I restore the history from the backups). This is currently probably the most annoying things with this: the bash history is lost every time.

Edit: proper bug report here with some more details and logs.
It also occurs when leaving the computer with the lockscreen for a while.
Sometimes the message is not displayed and it only shows a black screen with a mouse cursor (logs also at the bug report).

  • 1
    The more important question is why you're using Wayland in the first place other than hearing that it's "cool" "modern" and "new". The second question why you're using a distro which is so ill-advised to run the desktop. The third question, if Debian + Wayland are so unstable for you why are going through all this trouble? Dec 31, 2021 at 0:16
  • This question is about ways to find clues about problems (especially the described particular problem) of Wayland under Debian/KDE. Anyway, I chose Wayland because it looks like it'll replace Xorg anyway sooner or later, is better for security, and (the reason for why now; I asked about this a few days ago) solves the screen tearing problems of video files.
    – mYnDstrEAm
    Dec 31, 2021 at 11:20
  • Tearing is not present in Xorg as long as you use Option "TearFree" "on". As for your other arguments they don't look sound and are the best example of "I've heard it's cool". To each their own. Again, Debian contains a severely outdated software stack while Wayland support in KDE is a work in progress even as of now. phoronix.com/… Dec 31, 2021 at 11:23
  • Well I could still switch back any time if needed. I mean there must be some logs and ways to debug problems like this or not? I don't have this option (and didn't before switching to Wayland). If it's a solution to the screen tearing / video glitches problem please post it at the question about it: unix.stackexchange.com/q/684319/233262. At community.kde.org/Plasma/Wayland & community.kde.org/Goals/Wayland there's no info about troubleshooting problems like this.
    – mYnDstrEAm
    Dec 31, 2021 at 11:40


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