https://bugzilla.kernel.org/show_bug.cgi?id=67571
--- Comment #17 from Eric Valette eric.valette@free.fr --- So It did a simple 'mv SUMO_uvd.bin.mov SUMO_uvd.bin.mov' in the /lib/firmware/radeon directory, and now X11 works correctly. Problem is that without uvd, I can't use a E350 as an HTPC as it will never decode blueray quality in software.
Attached the new dmseg.