https://bugs.freedesktop.org/show_bug.cgi?id=61182
--- Comment #37 from Alex Deucher agd5f@yahoo.com --- (In reply to comment #35)
Wait: according to http://dri.freedesktop.org/wiki/GART/ the GART seems to enable the video card to access the computer's memory, not the other way around. So I don't see how this is relevant: we're getting a crash in a CPU instruction that is trying to access the video card's memory.
GART and VRAM are separate. As I said in comment 12, I though there may have been two issues at play at first, but upon further debugging, it appears to just be the vram window.