https://bugs.freedesktop.org/show_bug.cgi?id=62959
--- Comment #44 from Alexandre Demers alexandre.f.demers@gmail.com --- (In reply to comment #43)
3.6.11 was OK but also maybe is kinda 'old'.
Then try a 3.7 kernel if possible to see if a first bug was introduced there or if it all happened in the 3.8 branch. If I remember correctly, there were some changes about VM in 3.7 and some others about DMA in 3.8. Doing so should allow us to work on one bug/change at a time.
Are you using latest mesa, drm and ddx?