(In reply to Rafał Miłecki from comment #277) 
> Don't start the bisect again, just try the commit Michel told about.
> 
> git reset --hard 77497f2735ad6e29c55475e15e9790dbfa2c2ef8
> 
> Then compile the kernel, install it & test for few days.

This will work even if I no longer have git directory from that bisect ?
I mean, I'm on a clean system, starting all over again with :
$ git bisect start -- drivers/gpu/drm/radeon
$ git bisect good v3.16
$ git bisect bad v3.17
Bisecting: 57 revisions left to test after this (roughly 6 steps)
[03f62abd112d5150b6ce8957fa85d4f6e85e357f] drm/radeon: split PT setup in more
functions
$ git reset --hard 77497f2735ad6e29c55475e15e9790dbfa2c2ef8
HEAD is now at 77497f2 drm/radeon: Pass GART page flags to
radeon_gart_set_page() explicitly