Re: PCI IRQ routing problem in 2.4.0

[Tim Hockin]

> > Device 00:01.0 (slot 0): ISA bridge
> >   INTA: link 0x01, irq mask 0x1eb8 [3,4,5,7,9,10,11,12]
> >   INTB: link 0x02, irq mask 0x1eb8 [3,4,5,7,9,10,11,12]
> >   INTC: link 0x03, irq mask 0x1eb8 [3,4,5,7,9,10,11,12]
> >   INTD: link 0x04, irq mask 0x1eb8 [3,4,5,7,9,10,11,12]
> 
> Your "link" values are in the range 1-4. Which makes perfect sense, but
> that's absolutely _not_ what the Linux SiS routing code expects (the code 
> seems to expect them to be ASCII 'A' - 'D').

In reading the PIRQ specs, and making it work for our board, I thought
about this.  PIRQ states that link is chipset-dependant.  No chipset that I
have seen specifies what link should be.  So, as this case demonstrates, it
may be 'A' - the value the chipset expects, or 1, the logical index.
Either one makes sense, assuming the PIRQ routing code knows what link
means.  Here we see two BIOS vendors/versions that apparently do it
differently for the same chipset.    Grrr.