Re: [patch] io-apic-2.1.98-B

Linus Torvalds (torvalds@transmeta.com)
Sun, 26 Apr 1998 21:16:36 -0700 (PDT)


On Sun, 26 Apr 1998, David S. Miller wrote:
>
> I'd like to have the self-IPI part, but I would _really_ really
> prefer to not have the counter, until somebody convices me that it
> has to be there (and that implies giving a reason other than "some
> ne2000 card has problems", because the problems you see sound like
> they might be problems for other people regardless of any io-apic
> issues).
>
> Ok, but one question, to a clueless driver developer, what should we
> expect him to think that:

Note that the counter I was talking about was the "counter of delayed
interrupts", ie the counter that tells us how many interrupts happened
during processing of another interrupt or during "disable_irq()". I think
that counter should not be a counter at all, but a single bit of
information, because that is how the hardware does it for all other cases
where we disable interrupts.

> disable_irq(x);
> ... some stuff ...
> disable_irq(x);
> ...
> enable_irq(x);
> ... some stuff ...
> enable_irq(x);

The nesting of disable/enable_irq() is a totally different issue, although
there too I think that the counter is (a) not very useful and (b) not how
it has ever beed done before.

However, for this case I don't actually care all that much, because nobody
should be using nesting anyway, and as such I prefer it to not be a
counter.

> does? On the Sparc we treat it the way you think it should work
> (enable_irq() turns it on and no depth checking is done) however our
> case is different since we've written and maintain all our drivers and
> like to not think of ourselves as clueless driver developers ;-)

Just wait for when the Sparc enters the real world instead of the little
sheltered play-pen of Sun.

Linus

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