Hi Martin, kernel-image-2.6.10-powerpc (2.6.10-3) is working without this issue on my Powerbook G4 1.5 GHz, ATI Mobility Radeon 128 MB.
On 2.6.8 I haven't seen this bug, but another one: It seems to be impossible to configure X so that it isn't flickering at all. Either you use 'append="video=ofonly"' in /etc/yaboot.conf in order to avoid a slight horizontal flickering already visible in text mode, then there's only a wild flickering when you start X. Or you use 'append="video=radeonfb"' in order to make X usable, but then this slight horizontal fllickering remains also in the graphical mode. See also <http://debianhelp.org/modules.php?op=modload&name=phpBB_14&file=index&action=viewtopic&topic=7267&30654> So if you are going to release sarge with 2.6.8, then there will be computers that won't work with Debian stable for probably another 3 or 4 years, regarding the release cycles of Debian. So Sarge will be out of date when released. The only possibility would be to use testing or unstable, which sometimes is what the name says, or another distribution or Mac OS X (which is what I'm doing most of the time anyway). But at the moment 2.6.10-3 is in testing/sarge. Do you want to downgrade? Jens Arcor-DSL: die echte Flatrate für alle Bandbreiten. Jetzt ohne Einrichtungspreis einsteigen oder wechseln. Arcor-DSL ist in vielen Anschlussgebieten verfügbar. http://www.arcor.de/home/redir.php/emf-dsl-1