RE: PCI IRQ routing problem in 2.4.0 (updated patch)

[Dunlap, Randy]

> From: Martin Diehl [mailto:[e-mail]]
...
> Linus' patch helps you, because it makes us trusting the 
> device's config
> space over the routing table. Probably a good idea as long as BIOS'es
> wouldn't start to set wrong values in config space too...
...
> in fact vanilla 2.4.0 did believe what the bios states, 
> namely the broken
> routing table. It didn't believe however what the devices config space
> reports - which turned out to be correct.

The PIRQ (PCI IRQ Routing table) is a Windows 95/98 convention
(requirement).  It isn't used by NT or Windows 2000.
IOW, Linux needs to be well-prepared for handling interrupt
routing in the absence of the PIRQ table.
[http://www.microsoft.com/HWDEV/busbios/PCIIRQ.htm]

~Randy