https://bugs.freedesktop.org/show_bug.cgi?id=60802
--- Comment #64 from Alexandre Demers alexandre.f.demers@gmail.com --- (In reply to comment #63)
Created attachment 76592 [details] [review] take 5
After further investigation this seems to be an alignment issue with large block sizes on the DMA engine on cayman. For now just use the blitter for large block sizes.
It does the trick for now.