I was running the latest NetBSD 1.5 with Generic kernel.
as far as i know PC164 does not have this problem.
this problem related to Miata hardware only. (Miata GL is okay).
FYI :
http://lists.openresources.com/FreeBSD/freebsd-alpha/msg02070.html
and look for "DMA bug" in Miata category.

At 01:45 PM 3/4/01 -0800, Matthew Jacob wrote:

>BTW- On two different PC164s I've had really bad expriences with the Qlogic
>2100 (FC) card- it just doesn't work in 64 bit slots. The 1080 should- I don't
>believe the problems here are 64 vs. 32 bit slot related.
>
>In all of your mail, you didn't mention what release you're running.
>
>On Sun, 4 Mar 2001 night@suhar.dhs.org wrote:
>
> >
> > > > I've got Qlogic QLA1080 card which is 64-bit PCI card.
> > skip
> > > > Where can i find a list of compatible 64-bit devices which should
> > > > work fine with DEC PWS 500a? i searched Compaq website,
> > > > but could not find anything, but firmware update.
> > >
> > >QLA1080 is not on the compat list. Only QL1040 are.
> >
> > but 1040 is 32-bit PCI. 32-bit PCI should be compatible without any 
> problems.
> > i was looking for list of 64-bit PCI devices.
> >
> >