Yesterday I switched my openSUSE repos to 4.11.0 from factory (the beta repos) no problem
Today I upgraded to the 4.10.7 kernel from 4.10.6 (iirc) and KDE would not start after reboot
When KDE would not start I downgraded kernel to 3.9.8 (as that's what I had on disk)

KDM starts fine, selecting KDE as any user inc root and the screen blackens then comes back to the login screen
XFCE starts up fine inc using kwin, composting and any KDE apps

looked at the logs and didn't see anything (but not sure what to look for)

in /var/log/kdmlog I found:

Code: Select all

trying to create local folder /root/.kde4: Permission denied
trying to create local folder /root/.kde4: Permission denied
kdmgreet(3049)/KSharedDataCache KSharedDataCache::Private::mapSharedMemory: Failed to establish shared memory mapping, will fallback to private memory -- memory usage will increase
Fatal Error: Accessed global static 'KGlobalPrivate *globalData()' after destruction. Defined at /home/abuild/rpmbuild/BUILD/kdelibs-4.11.0/kdecore/kernel/kglobal.cpp:127
KCrash: Application 'kdmgreet' crashing...
Fatal Error: Accessed global static 'KGlobalPrivate *globalData()' after destruction. Defined at /home/abuild/rpmbuild/BUILD/kdelibs-4.11.0/kdecore/kernel/kglobal.cpp:127
Unable to start Dr. Konqi
Server terminated successfully (0). Closing log file.

Where to look?

thanks,

The errors in KDM log are likely related to the "KDE would not start" issue from the new, buggy kernel.
Can you check ~/.xsession-errors from a user you have tried to login as?

no users were able to login to KDE including root

found the issue in .xsession-errors, was missing the file startkrandr that is called in startkde, somehow lost it when switching repos

as always thanks,