But it works when I start X manually before stopping them again and running gdm. It's explained at:
In my case, it's caused by this:
And this patch fixes the problem:
Thanks for applying it
Looks like upstream is still undecided about this patch. A workaround is to disable rc6 using i915.i915_enable_rc6=0 kernel parameter.
looks like this was the final commit as I can read in upstream report:
Fixed in mesa-9.1.3