https://bugs.freedesktop.org/show_bug.cgi?id=82455
--- Comment #1 from Michel Dänzer michel@daenzer.net ---
radeon 0000:01:00.0: bo fffff801f3ee2c00 va 0x00000000 conflict with (bo fffff801f3ee3000 0x00800000 0x00802000)
Looks like the Mesa radeon winsys is not assigning GPU virtual memory addresses correctly (0x00000000 is not a valid virtual address).
You might have better luck with that with current Mesa Git master, but note that the Mesa radeonsi driver needs a lot of work before it has any chance of working correctly on big endian hosts.