Comment 37 for bug 181343

continued from Swift:

*** Running kdm from KDE4 ***
The Nvidia module crashed and reports backtrace in /var/log/kdm.log
(Driver 96.43.05). Sorry I don't have it anymore.

Found a workaround I've read somewhere else:
Add the following line in [X-*-Core] stanza in /usr/lib/kde4/etc/kde4/kdm/kdmrc file
TerminateServer=true
(You'll get X fully restarted, kill + restart, and the Nvidia Logo that you can remove
in xorg.conf file)
Logout still has a weird delay, but eventually works and gets back to Welcome screen.