Re: IRQ routing / assignment issue

[Robert Hancock <hancockr@shaw.ca>]

Radu Rendec wrote:
> Hi,
> 
> I'm trying to make the kernel assign different irqs for two NICs
> connected to _separate_ pci buses. Messing around with pirq= kenrel
> parameter didn't seem to change anything.

The kernel doesn't really have any way to change the physical 
device/slot to IRQ mapping. In some cases there are BIOS settings which 
might influence this, but in most cases it's impossible to change (i.e. 
devices physically wired to the same IRQ line).

> 
> The machine is a smp (dual-xeon). Relevant lspci output is:
> 01:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721
> Gigabit Ethernet PCI Express (rev 11)
> 02:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721
> Gigabit Ethernet PCI Express (rev 11)
> 
> IRQ assignment dmesg output is:
> ACPI: PCI Interrupt 0000:01:00.0[A] -> GSI 16 (level, low) -> IRQ 16
> ACPI: PCI Interrupt 0000:02:00.0[A] -> GSI 16 (level, low) -> IRQ 16
> 
> At the moment I'm almost clueless about how irq routing / assignment
> works (either in general or in linux), so any suggestion would help -
> even "rtfm" would be helpful, as long as you specify what is the
> appropriate manual ;)
> 
> If you are so kind to reply, please include my address in cc (I'm not
> subscribed).
> 
> Thanks,
> 
> Radu Rendec
> 
> 
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