Cannot login / segfault in libKF5WaylandServer

Upgraded to Tumbleweed 20191022 (32bit). I no longer can login due to crash in process [kwin_wayland].
Screen is black, no input is accepted on keyboard. When I remotely login via SSH, in /var/log/messages I find:

kernel:    82.434303] kwin_wayland[1820]: segfault at 8 ip b790d5e4 sp bfe762ec error 4 in ibKF5WaylandServer.so.5.63.0[b78e2000+6a000]

How to proceed?
Tnx in advance

Use KDE Plasma5 on X11, and see if that works OK ( It should ).

Not sure what you want to tell me since X11 is the basic underlying graphical system. The login screen gives me the choice of Plasma/Plasma (wayland)/plasma (full wayland). Neither of them leads to a successful login. Only console login is possible; but only before I try to login with X11.

This is my first serious problem since I started using OpenSuSe in the early 90s.

That’s three choices. I’m not sure whether you have tried all three, because your use of “neither” implies only two (but could be a language translation issue). Knurpht was suggesting that you try the first (plain “Plasma”).

Sorry, my fault. Should have written none of them. However I tried all three choices.
Using plain “Plasma” gives different results: Screen is blank, monitor displays “out of sync” but keyboard remains
responsive and I can switch to VT1. No errors in “X,.org.0” logfile, a huge bunch of messages about DBus errors in “/var/log/messages”. Result: screen is unusable. Will try to find some relevant information in the logfile.
Tnx anyway so far!

Rollback to before the upgrade, then try upgrading again.

TSU

How did you update your TW install ?

Solved.

I started to restore my backups until I found a version where plain plasma worked. The last version where plain plasma worked was 20190927. Then I run zypper dup . A rother time consuming job but it now works again.

Sorry for the noise and thanks for your patience.