Hi there!
I've got a strange issue for a while now: on every boot, i get the message "composition has been suspended by another program", as i resume my session i can't really figure out which one that would be.
I tried the ENV "QT_LOGGING_RULES=kwin_*.debug=true" according to https://community.kde.org/KWin/Debuggin ... log_output but i don't get a ~/.xsession-errors file. Is there any other logfile that i didn't find yet, that might enlighten me which program is suspeding the compositor?

I use sddm as my display manager, and my .xsession-errors file is now at ~/.local/share/sddm/xorg-session.log. You might check there, or the corresponding directory for your display manager.

If that doesn't give you the answer, I would try disabling everything optional that starts when you log in, and then, if the problem goes away, re-enable everything one by one to figure out what is causing the problem. In Systemsettings->Stattup and Shutdown->Desktop session, check "Start with an empty session". Also, try disabling everything in the Autostart settings.

Thanks for your answer!
Unfortunately i can't find any hint in xorg-sessions.log.
Your other approach would certainly work, i was just hoping for something less...manual and labour intensive ^^

As i can't really figure out what is disabling composition (but apparently, if anydesk is automatically loaded it works every time?!), i'm now trying to force it with a script. Running "qdbus org.kde.KWin /Compositor resume" doesn't work after a reboot unfortunately, so now i'd like to use xdotool to send an L_alt+L_shift+F12 a few seconds after login. Unfortunately, this DISABLES composition if it happens to be working from time to time...

So the question is: is there a way to figure out if composition is active in a bash script?