Xfree86 4.3.99 Radeon DRM driver don't work properly into kernel 2.6 and new iBook G4. Using kernel DRM module for Radeon suffer of some "fliking" of the laptop iBook G4 lcd. Using kernel 2.4 and emerging external "xfree-drm" the problem was solved. Same problem do not seems to be on pBooks and previous iBook
Please confirm using xorg-x11, we aren't interested in supporting xfree 4.3.99.
Closing due to lack of info; please reopen if you add more.