> > It makes me think that XF4 is doing things to the 2940 that it
> > shouldn't..
>
>So... any suggestions on how I can track this problem down?

A quick guess would be that XFree is setting a region that overlaps
the 2940's register space as allowing write combining.  You should
be able to determine if this is a problem by looking at the XFree86
logs and correlating its actions with the register window for the
2940.  You could also force the 2940 to use PIO, but I'm not sure
how you'd do this in NetBSD.

--
Justin