[linux-audio-user] audiophile 2496 - spdif in

wes schreiner linux-audio-user@music.columbia.edu
Thu Oct 9 06:42:01 2003

jordan muscott wrote:

> Ok to be honest I'm not gonna switch distros...... but are you saying 
> that Redhat offers you extra software that allows you to change the 
> IRQs that your pci cards are on?

There is no such software on any distro. Your motherboard's BIOS decides 
which PCI slots get which IRQs. In a few motherboards the BIOS lets one 
select which IRQs get assigned to certain slots, but most don't. So with 
most motherboards all one can do is move cards around to different slots 
and then see what IRQ gets assigned. If your sound card and your 
ethernet card are sharing an IRQ, that's because those PCI slots used 
both have the same IRQ assignment. If you swap just those two cards 
slot-for-slot they will end up with the same IRQ again. Try moving just 
one of the cards to another slot. If all of your slots are full then 
move multiple cards.

On some motherboards with some processors you can turn on Local APIC 
support in your kernel config and get more IRQs to work with. Dual 
processor motherboards, even if they have only one CPU installed, can do 
this to get more IRQs. If you have dual CPUs you should already be 
running a SMP kernel and you probably don't have IRQ assignment 
problems. If you do, it's back to juggling cards.