https://bugs.freedesktop.org/show_bug.cgi?id=74347
--- Comment #5 from higuita@gmx.net --- Sorry, i must have changed the bug component by accident, as i don't recall touching it.
R600_DEBUG=nocpdma is almost working fine. i get some quick sporadic corruption (sometime a few seconds, other times almost a minute between corruptions)
I will reboot with AGP disable and see what happen.