I have a multiseat configuration with 2 cards, each connected to 2 monitors. (Total 4 monitors)
The second card (read: seat) of my multiseat configuration has a corrupted output after suspend - however hibernation works fine.
Created attachment 85814 [details]
corrupted screen (image)
Created attachment 85815 [details]
Created attachment 85816 [details]
Created attachment 85817 [details]
Xorg.1.log (corrupted X screen)
Created attachment 85818 [details]
Xorg.0.log (working screen)
Restarting the X Server would restore the correct colors. however this is not a real fix as running X sessions are lost.
The bug is still present with 3.12-rc7