2.6.13 ati (ibook) frambuffer problem

Hi,

after upgrading to a vanilla 2.6.13 kernel (from 2.6.12) there seems to
be a problem with the framebuffer driver I use for my ibook. The display
statz at the opnpic message, and after a while the machine reboot (looks
like panic().

Can someone confirm? Or better, point me to a patch ;-)?

For given reason, what is the common method to debug crashes before the
display is working?

TIA,

Joerg