(In reply to Paul Menzel from comment #2)
> Just as a follow-up, the long time seems to have been caused by ftrace.
> 
> With the patch below on top of drm-tip from this morning, it only takes 7
> ms. 

Interesting. I wasn't aware that ftrace could have such negative side effects.

Anyway if somebody has a radeon in a box with halve a TB system memory he can
probably live with a few ms resume time :)