Maybe unrelated to this bug report, but with today's Linus' master
(04012e3076943f17c8cfc77a196701c8f0b8964f) the only suspend/resume issue left
is that I get:

[drm:rv770_stop_dpm] *ERROR* Could not force DPM to low.

in dmesg upon resume.

That is before the 'ring' and 'uvd' messages. It seems harmless, I didn't
notice any problems. It can switch power levels later on, play videos via
uvd... it just seems to try to do something with dpm too early in the resume
process.