(In reply to comment #5)
> (In reply to comment #4)
> > bisected and first bad commit is: 8696e33f06b0c52195152cc6a0e3d52233f486c1
> > commit 8696e33f06b0c52195152cc6a0e3d52233f486c1
> > Author: Alex Deucher <alexander.deucher@amd.com>
> > Date:   Thu Dec 13 18:57:07 2012 -0500
> > 
> >     drm/radeon: bump version for CS ioctl support for async DMA
> >     
> >     Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> 
> That just enables the use of DMA by the 3D driver, so the issue is in mesa. 
> This looks like a duplicate of bug 60236.

You are right, that's what I thought about the bad identified commit.

I don't have the same symptoms as in bug 60236, but I'll have a look anyway.
Otherwise, I'll use kernel 3.8-rc7 and I'll bisect mesa to track the bug down.