On Tue, Mar 12, 2002 at 10:04:12AM +0000, David Laight wrote:
> On Tue, Mar 12, 2002 at 08:58:34AM +0100, Manuel Bouyer wrote:
> > On Mon, Mar 11, 2002 at 10:49:02PM +0000, David Laight wrote:
> > > What is wrong with the 'alternate' status register?
> > > (returns the same as the status register but without
> > > clearing the IRQ).
> > 
> > Not all controllers provide it :(
> 
> Is this one of the things that separate an ATA disk from a wd one?

Not only, some ATA controllers don't provide it (I think one of them is on
atari, or amiga, I don't remember).

> > 
> > > OTOH is is perfectly possible to write an ATA driver
> > > that will never unintentionally clear an IRQ.
> > > 
> > > Also, the interrupt loop would be caused by FAILING to
> > > remove an IRQ, not by removing one when it shouldn't be.
> > 
> > Yes, but you can also remove one when you shouldn't, and this can lead to a
> > lost interrupt.
> 
> But that isn't what the problem was!

Yes, but if you change the code this way to solve the problem, you'll create
another one.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
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