[LAU] Something interesting about kernel 3.6.5-rt14

[Len Ovens]

On Sat, November 3, 2012 4:23 am, Ralf Mardorf wrote:


> if I remove all USB stuff I still see irq/18-ohci_hcd [1].

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,
uhci_hcd:usb5, nouveau
 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.

-- 
Len Ovens
www.OvenWerks.net