Ian Dall wrote:
> intr_established are enabled.  So, I created IPL_RTTY at slightly
> higher than IPL_TTY. This is a definite improvement. It could be made
> even    higher, but I don't think that would help.

It really helps? Note that on the pc532 the only change that is done to
the current priority level when handling an interrupt is to disable
this interrupt. If the handler has to run at a specific priority level,
it has to do a call to splxxx on his own.

> The scsi driver has to do transfers in one direction (read I
> think) with all interrupts disabled. At very high serial baud rates,
> it is easy for interrupts to be blocked out for long enough for the
> fifo to overrun.

Yes, at least reads are done (and have to be done) with interrupts
disabled. I think do it for writes as well. Does anyone understand
why we have to disable the interrupts for reads at all?

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