#945562 libqt5core5a: Update to 5.12 breaks KDE login

Package:
libqt5core5a
Source:
qtbase-opensource-src
Description:
Qt 5 core module
Submitter:
David Engel
Date:
2019-12-08 17:27:02 UTC
Severity:
important
#945562#5
Date:
2019-11-26 23:58:22 UTC
From:
To:
Dear Maintainer,

I had not rebooted my Deiban/testing system since mid-October.  When I
did, my KDE session was unustable.  After entering my password into
sddm, the screen began flashing wildly with my restored session
windows visible between the flashes.  The end result was a mish-mash
of the KDE login animation and my restored windows and a system that
was unresponsive to keyboard input and mouse clicks.

After much trial and error and several system restores from backups, I
narrowed the problem down to upgrading from qt version 5.11.3+dsfg1-3
to version 5.12.5+dsfg-2.  I suppose there is a slight chance that the
latest versions of libkf5xmlgui and plasma-integration are also to
blame since the qt upgrade forced them to be upgraded too.

I'm currently forced to use XFCE since KDE is unusable.
Interestingly, KDE programs like konsole and dolphin show no ill
effects when run under XFCE.  The mythtv installation I build myself
and uses Qt and OpenGL also works fine.

The problem does not appear to have anything to do with my personal
KDE configuration.  I created a dummy user with no existing
configuration and the problem still occurred.

Finally, the problem does not occur on another system that I maintain
which uses the nvidia-legacy-390xx graphics driver.  Perhaps the
problem is related to something in the intel graphics driver on this
old, Ivy Bridge system.

Please let me know if there is any other information you want me to
provide like logs or things you want me to try.

David
#945562#10
Date:
2019-11-27 02:54:09 UTC
From:
To:
I forgot to mention one additional thing.  After qt is upgraded to
5.12, the sddm login screen hints at a problem.  If I move the mouse
cursor around, especially crossing over the buttons and text entries,
the screen very briefly flashes to another image.  The login screen
remains functional, though, and I can succesfully log into any other
desktop environment except KDE.

David
#945562#15
Date:
2019-12-08 17:15:50 UTC
From:
To:
Hi David!

This really sounds like a video issue. So far we did not receive any
other complain in this regard.
Try checking /var/log/Xorg.log.0 (after trying to start KDE) for
possible issues.
#945562#18
Date:
2019-12-08 17:22:16 UTC
From:
To:
Sorry, I mispelled the e-mail address in my reply. Please see
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=945562#15