Thursday 09 October 2003 12.26 skrev wes schreiner: > 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. > > wes Hi, I'm pretty sure I've read that APIC is a no no and should be avoided. Here's a link to some interesting info about "normal" IRQs in a PC. There is more to it than just having an "OWN" IRQ, they have different priorities. http://myweb.cableone.net/eviltwin69/Arcana.html#IRQs See also (the source) http://www.djcj.org/LAU/guide/Low_latency-Mini-HOWTO.php3 /Robert
