[...]

>
> I'm not cluefull enough to know why DMA would cause the machine checks -
> obviously something's getting fratzed on a bus somewhere.  Is this more
> likely to be a driver or hardware problem?

I definitely recall reading something like "earlier models of *** had
problems
with *** chip". I'm not sure whether it was about DMA chip (quite likely)
and
the pc164. I tried to dig in mail archives and failed :-(

Some opinions from discussion of this problem from redhat axp-list :

http://www.lib.uaa.alaska.edu/axp-list/archive/2000-01/0032.html
"I think this is more likely a programming problem. This error
can be caused by accessing non-existent memory. The pyxis chip
ECC checking is mainly done when non-processor accesses are
occurring, such as PCI bus master DMA, and getting a double bit
error is very unlikely if you have not gotten any single bit
errors. Other things which can cause it are PCI bus parity
errors and PCI bus time-outs. "

>
> Simon.

Andrei