Re: [PATCH] 2.5.68 Fix IO_APIC IRQ assignment bug

[Zwane Mwaikambo]

On Sun, 20 Apr 2003, Linus Torvalds wrote:

> Good call.
> 
> Although I suspect you need about a million interrupt sources to hit
> this, since FIRST_SYSTEM_VECTOR is somethign like 0xef, and thus you can
> hit it only when "offset" has already been incremented seven times
> (which implies that we've walked the whole vector space quite a few
> times by then).
> 
> Did you actually see this on hardware?

Yes, we need to bail out in assign_irq_vector when we wrap around, 
otherwise we cause collisions when programming the IOAPIC. And we also 
need to avoid overruning NR_IRQS structures in setup_IO_APIC_irqs.

	Zwane