BTW, I skimmed through ite_rt.c esp. screen_up, and it seems that it
is the NCR chip that does the scrolling.  This means you're not out of
luck, if you cannot get the things to work using this method, There's
always the option of letting the CPU take care of it.  It *is* strange
that you should just see this on an 040 system.  Perhaps your kernel
sets up the cache info wrong wrt the retina buffer.  I really don't
know.  Perhaps you should try a current kernel as well, the zbus setup
has changed slightly, although I don't think it will help you.

Anyway, keep us informed.

Niklas