Re: [PATCH] x86/sfi: fix ioapic gsi range

From: H. Peter Anvin
Date: Tue Jun 08 2010 - 14:11:50 EST


On 06/08/2010 01:10 AM, Alan Cox wrote:
>>> You may not use a 1-1 mapping if you don't have legacy irqs. Linux
>>> irqs 0-15 are the ISA irqs you may not use those irq numbers for
>
> Linux IRQ 0 is "no IRQ assigned", except buried in certain bits of arch
> specific historical knowledge.
>
> Also calling 1-15 ISA IRQ lines is also somewhat misleading given they
> are almost certainly routing for PCI devices. "PIC IRQ routing" maybe -
> but even that is not really true on a lot of PC hardware today except by
> convention.

Yes, but I gather IRQ/GSI 0 is an early-acquire primary timer on MRST on
Moorestown just as on PC/AT... just a different one. Hence "special" in
the same sort of way. I don't really care, personally, though.

-hpa

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