On Sat, November 3, 2012 4:23 am, Ralf Mardorf wrote:
> if I remove all USB stuff I still see irq/18-ohci_hcd .
Ya, they will always show up because the ports are there. But if nothing
is plugged in there should be no interrupts generated. If you look at cat
/proc/interrupts, you will see which USB ports are are hooked to which
IRQs. Mine shows:
16: 353468 0 IO-APIC-fasteoi uhci_hcd:usb2,
17: 292646 0 IO-APIC-fasteoi eth0
18: 1537 0 IO-APIC-fasteoi ata_piix, uhci_hcd:usb4
19: 0 0 IO-APIC-fasteoi uhci_hcd:usb3
20: 0 0 IO-APIC-fasteoi snd_ens1370
21: 255695 0 IO-APIC-fasteoi snd_ice1712
23: 334006 0 IO-APIC-fasteoi ehci_hcd:usb1
In my case I was able to move my sound card out of the pci slot that it
was sharing with USB1. You can tell which USB port is which by plugging in
a USB memstick and looking at the last few lines of dmesg to see which USB
port it is (great for finding the best port to plug a sound IF into BTW).
You notice also that I tried to set the sound card I use for recording to
a higher irq than the ens that I use as a midi card. Just switching those
two around made a difference. I happen to have 5 pci slots to play with as
this is an older machine.
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