I'm getting this error from time to time on my 945gm with latest stable kernel (184.108.40.206 with gentoo patches). I've noticed that it's really easy to reproduce this bug with kde 4.4rc1 - just switch plasma to netbook mode.
Video driver components versions:
Created attachment 24598 [details]
part of syslog
As you can see in attached log, "[drm:i915_gem_object_pin] *ERROR* Failure to install fence: -28" message preceeded subj message
It seems there's a fence leak somewhere
*** This bug has been marked as a duplicate of bug 15004 ***