By frost flicker I mean that when the radeon kernel framebuffer replaces vesafb
during boot the display flickers and "frosts up" (as it does when it's hanging)
then flickers back to normal. It's not a big issue tho.

Anyways, after some hours of testing, the only real issue I spotted so far is
that the screen gets corrupted and the laptop hangs when waking up from sleep.
Didn't try hibernation as I have no swap partition. 
Else pretty much everything works, the temperature is stable at 50°C when idle
(which is awesome), forcing power modes and levels works.

Going forward to try your new patch now. Do I have to test it in combinaison
with the other no-ss one or alone ?