akmod-nvidia causing big problems on F15 system

[Dean S. Messing]

I recently did a yum update on my F15 which pulled in a new kernel, and
a lot of other packages.

After a reboot, KDE locked up. Eventually I got a message saying that
compositing (for Desktop Effects) had been turned off because my system
was too slow (which it is not.)

Thankfully I had done a full backup before the update so I restored the
old system and the problems vanished. I have KDE configured to use all
the nice Desktop Effects which makes heavy use of OpenGL.  It has run
flawlessly till this update.

I then began a process of elimination, restricting (for example) new KDE
packages from being updated, restricting the kernel from being updated,
&c. with restores of the old system in between. Every single trial hosed
KDE's operation.

After lots of trials I finally noticed that
akmod-nvidia-280.13-4.fc15.x86_64 was always being pulled in, so I
finally restricted that (and the new kernel) so that kmod-nvidia would
not be recompiled upon reboot.  Voila! No KDE problems.

One last experiment: I updated _only_ akmod-nvidia, rebooted to allow
kmod-nvidia to rebuilt and KDE was hosed.  Looking in Xorg.log I saw
a boatload of error messages like this

   KWin::checkGLError: GL error ( PostPaint ): ???

where ??? was a hex number (that, alas, I didn't write down).  A google
search at the time brought up nothing and I see no recent reported
errors with akmod-nvidia.

Might one of you nvidia wizards on the list know what's going on or
whatq I might do to diagnose the problem?


Thanks.
Dean