I don't know if this helps, but I tried a few combinations:
(1) radeonfb + X, usefbdev "yes"
(2) radeonfb + X, usefbdev "no"
(3) ofonly + X, usefbdev "no"1 and 2 leads to a yellowish X screen after resume 3 works. (on an iBook/g4 800 12") -- Sylvain Joyeux
