On Wed, Mar 04, 2009 at 10:32:11PM +0000, Keir Fraser wrote:
> On 04/03/2009 22:26, "Simon Horman" <horms@xxxxxxxxxxxx> wrote:
>
> >> Please note that _PRT method in ACPI AML should reflect GSIs. If you expand
> >> GSIs, it will be necessary to change the _PRT method. Please see
> >> tools/firmware/hvmloader/acpi/dsdt.asl.
> >
> > Could someone explain why the current code uses 32 GSIs rather than using
> > 128?
>
> 32 should be plenty, and I'd want to emulate multiple IO-APICs beyond that
> just out of fear that some OS will choke on an IO-APIC with 128 pins (since
> no real single IO-APIC has so many pins). It just seemed a bit unnecessary
> when this support was originally implemented. At this point I haven't heard
> any concrete evidence so far that 32 GSIs is insufficient in any real
> scenario. So that's what we'll be sticking with for the time being, I think.
Thanks, I will see if I can dig out any real-world reasons.
--
Simon Horman
VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
H: www.vergenet.net/~horms/ W: www.valinux.co.jp/en
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