Re: New kernel/resource.c

Richard Henderson (rth@twiddle.net)
Sun, 25 Jul 1999 12:27:33 -0700

On Sun, Jul 25, 1999 at 12:19:39PM -0700, Linus Torvalds wrote:
> I wonder how many devices decode all 32 bits of an IO address. Maybe they
> all do, but it sure hasn't gotten any testing by anybody. Considering that
> ISA devices even today often only decode 10 bits for historical reasons, I
> wouldn't find it surprising at all if there are PCI devices that only
> bother with the low 16 bits - and they'd be really unhappy with any
> aliasing...

I have no idea.

I do know, however, that that Contaq chip (combination PCI->ISA bridge +
IDE + other standard pc hardware) is one we consider special and don't
initialize, but leave to the previous console code. SRM in this case.
And that chip _does_ decode at least 17 bits, but probably all of them.

r~

PS: Don't ask me why it's special. Jay wrote that, and I presume for
a reason. Only recently do I have a machine that contains one. Perhaps
it's irrelevant now that we have a real IDE driver for it.

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