Re: irq routing on TigerMPX.

[ollie lho]

On Thu, 2003-07-24 at 04:37, Oleg Gusev wrote:
> It seems that linuxbios (and linux) uses the irq routing tables 
>  dumped from the bios mptable.
>  Are there any good reasons to reroute 9 pci/agp interrupts (2 64-bit slots
>  on the first pci bus + 1  agp + 4 32-bit slots + builtin ethernet on the  
> second pci bus) to 4 apic pins 16,17,18,19 when at least the pins 5,9,10,11
> are not used at all ? Now i have 3 devices sharing
>  pin 19, and 2 devices on 16,17 and 18. 
>  Is this the intended use of io-apic ?

Well, PCI spec only defines 4 IRQ Lines (A,B,C,D) and these lines are 
supposed to be shareable. These 4 lines are connected to 4 IRQ pins on
the apic. As a result, even apic has 24 irq pins, we allocate 4 pins
for PCI devices.