> > There is enough of the twm screen that when I put my mouse on it and click
> > and hold I get the drop down menu and can exit cleanly.  Keeping in mind
> > that about two thirds of my screen is white and I can't type on the rest.
> > By the way the arrow does traverse the whole screen.  I hope this gives you
> > some more insight.  Your help in this is appreciated.
> 
> Hmmm....it sounds to me like the kernel is mapping the display into the
> wrong part of video memory, although I'm not quite sure that's it....you
> might try a quick run with a -current kernel to see if the "madhatter"
> patch fixes it.  I'm sure that several other people will know a lot more
> about this than I, tho.

Yes. The address the grf driver is passing to X is messed up. The console
has the luxury of getting the address from the booter but the address
sometimes gets lost in the scuffle on the way to the grf driver and
you end up with some bizzaro offset.

The trouble has to do with the fact that the Quadra video system allows
you to set the video base address. I think that the grf driver is somehow
getting a hard-coded base address at slot $9 but the video can actaully
reside *virtually anywhere* within slot $9.

During my studies of the Quadra video driver I have found that Apple
deliberately ignores their own recommendation in Cards'n'Drivers
that says that the video base cannot change during mode changes.
During a mode change they move the video base past the current
screen to (apparently) reduce artifacts.

Luckily, I know how to get/set the video base address and enough folks
have been complaining about this problem that if I get a second this
weekend or something I might post a patch that should squash this
bug forever.