NetBSD VM crashing with 16M, NOT with 14.5M! - Solution!

[Chun Tham <ctham%acs.ucalgary.ca@localhost>]

Well, after recompiling the kernel a few times I have gotten the GVP-040
to run with the full complement of 16M 32-bit RAM...  It turns out that
the GVP SCSI ROM has problems DMA'ing to upper addressed RAM.  Therefore
what I did was just change the dmamask to 0x00000000 in dev/gtsc.c and
force the GVP to DMA into Zorro II RAM, removing a few messages in
dev/sbin.c.

I guess there must be a performance hit going thru ZII bounce buffers but
the system feels pretty fast and hasn't locked on me yet.  So, it turns
out that the 16-bit RAM is not the culprit, rather the GVP SCSI is...


Regards,
Joe Tham

Dept. of Psychiatry
University of Calgary
Calgary, Alberta, Canada