[coreboot] IRQ 9 on s2895 and s2892

Myles Watson mylesgw at gmail.com
Thu Mar 12 14:44:39 CET 2009

On Wed, Mar 11, 2009 at 5:20 PM, Rudolf Marek <r.marek at assembler.cz> wrote:
>> I booted again, and IRQ9 has 10x the interrupts as any other source.
>> I guess that means it's not a shared one?
> Hmm and MPtable has no entries for this IRQ? So it must be something else.
> It makes me wonder what changes trigger the irq9 storm. Perhaps kernel would
> complain even when there is none handler at all.
I think it says Spurious IRQ then.

> Any ideas what it could be? maybe booting irqroute=pic or smth like this
> could
> force the old way of pci routing... but leaving IRQ9 for acpi. Should be
> interesting test.
I'll try it.

> Maybe you have smth wrong in FADT? Dont know
Could be.  I've tried matching the factory and yours.

>> Won't I have to add IRQ 9 to the mptable?  Will it find it otherwise?
> If Irq 9 is not used then it must be something else. Is old coreboot  having
> MPtable entries >15?
Yes.  21,22,23...  I copied the interrupts for the DSDT from the MPtable.

> Or write simple kernel driver just requesting IRQ9 and
> returing IRQ_NONE with old coreboot. See if IRQ is busy too.

I'll look around, someone must have already written one.


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