Ian Dall wrote:
> Actually a few calculations imply that there *should* be no problem
> with the scsi pseudo dma. It transfers in 512 byte blocks. That is
> 512us at 1 MB/s which is less than 2 characters time at 38.4 kB and
> there is at least a 4 byte fifo.  However, there is no guarantee on
> how long the 512 byte block transfer will take. Hopefully and sensible
> scsi device with caches and the ability to disconnect and so on will
> not go and do a seek in the middle of a block transfer, but as I say
> there is no guarantee.

You could try adjusting TSIZE (in sys/arch/pc532/dev/ncr.c). The code
should work with this set to 128 as well. *But* also interrupts are
enabled every TSIZE bytes, your real problem may be a scn-interrupt
interrupted by a scsi interrupt. You could try protecting the
scn-rx-interrupt code with splbio.

Matthias
-- 
leo@dachau.marco.de			in real life: Matthias Pfaller
marco GmbH, 85221 Dachau, Germany	tel: +49 8131 516142