https://bugs.freedesktop.org/show_bug.cgi?id=91268
--- Comment #10 from Kajzer kap3tan@gmail.com --- (In reply to Michel Dänzer from comment #9)
That's expected. Alex's patch isn't a fix but just to confirm the problem is really directly related to write-combined CPU mappings.
Yeah I know, that's what I really asked for, a way to disable that commit. I can confirm now that indeed there's some bug in that commit (with R6xx chips) I had no hangs with mappings disabled. I'm willing to test potential fixes.