Re: ncr53c8xx + tulip IRQ sharing

Rogier Wolff (R.E.Wolff@BitWizard.nl)
17 Feb 1998 19:33:18 +0100

Doug Ledford wrote:
> > I didn't realize my question and lame BIOS would spark such a lively
> > debate. Anyone care to guess which is the best way to procede? Make the
> > NCR driver use slow interrupts? Make the Tulip driver use fast ones? Try
> > to somehow force them onto different IRQ's without the BIOS's help?
> >
> > Note...I'm looking for a solution usable with 2.0.x. A possible solution
> > requiring 2.1.x has already been suggested, but I'd rather not go there
> > yet.

> I'm not sure about Rogier's comments in regards to 2.1.z, but in
> regards to 2.0.x, your interrupt handler will never get called more
> than once regardless of the flags in use. The difference is that
> with the SA_INTERRUPT flag, your handler is called with global
> interrupts disabled (cli() state) and upon return the sti() state is
> restored and the irq is ended without any further activity. This
> means that there is no bottom half [....]

The ncr driver in 2.0.33 would work without the SA_INTERRUPT flag,
when you change the two "#if 0" into "#if 1" in the ..._intr routine.

My guess is that it is probably also safe without that change too, but
I haven't tested that.

Roger.

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