FWIW, the problems I was talking about have vanished after today's
update.
Probably had to do with one of these....
May 30 07:00:07 Updated:
mesa-dri-filesystem-7.11-0.11.20110525.0.fc15.x86_64
May 30 07:00:08 Updated:
mesa-dri-llvmcore-7.11-0.11.20110525.0.fc15.x86_64
May 30 07:00:16 Updated: mesa-libGL-7.11-0.11.20110525.0.fc15.x86_64
May 30 07:00:19 Updated: mesa-libGL-7.11-0.11.20110525.0.fc15.i686
May 30 07:00:25 Updated:
mesa-libGLU-7.11-0.11.20110525.0.fc15.x86_64
May 30 07:00:27 Updated:
mesa-dri-drivers-7.11-0.11.20110525.0.fc15.x86_64
May 30 07:00:38 Updated: mesa-libGLU-7.11-0.11.20110525.0.fc15.i686