On Tue, Aug 24, 2010 at 5:10 AM, David Santamauro <david.santamauro@xxxxxxxxx> wrote: > > Hi, > > I've decided to get back to diagnosing why my delta 1010 inputs have a > background noise and stumbled across a few websites indicating that the > problem could be irq sharing. > > My delta shares irq 20 with usb devices: > > $ cat /proc/interrupts |grep ICE > 20: 1325915 1326971 1335010 1348560 1337725 > 1330100 1336582 1346152 IO-APIC-fasteoi ehci_hcd:usb1, > uhci_hcd:usb2, ICE1712 > > Is there a way to forcibly assign ICE1712 to another IRQ? I just want > to test the theory. > > thanks > > David IRQ's and their numbering are physical things. Their assignment is made, fundamentally, when the motherboard is designed and is hardwired based on the PC board traces. You cannot change those. For desktop machines the control you do have is to move PCI devices to different PCI slots. Asus motherboards are usually pretty good about calling out what slots share interrupts with other devices. Check your MB manual. If you don't have a manual use your eyes and think about the whole IRQ list. (Not just the part you showed.) Look for another PCI card that seems to be on an interrupt by itself and then switch that card with your sound card. For USB devices, if you have multiple USB controllers and _if_ they use different IRQs, then you may be able to choose a different controller by choosing a different USB connector to plug into. Move your USB devices if this appears to be true about your motherboard. (It is on many of mine...) Note that sharing IRQs with a USB controller isn't necessarily bad. It depends on what sort of USB device is attached, how its driver is written, and how many interrupts it generates. However, all things being equal, it's better if everything is completely separated as that allows very little interaction. Hope this helps, Mark _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
