Re: IO APIC IRQ assignment

From: Keith Chew
Date: Tue May 30 2006 - 09:25:58 EST



You could try enabling "Bus Options" ->
[*] Message Signaled Interrupts (MSI and MSI-X)

or in .config
CONFIG_PCI_MSI=y

It only works for PCI devices.


Yes, the 2 devices are PCI devices. We tried enabling CONFIG_PCI_MSI,
also tried pci=routeirq, but cat /proc/interrupts still show the
devices sharing the same IRQ. It is interesting how each of these
options (ie routeirq, CONFIG_PCI_MSI, noacpi, etc) causes the kernel
to assign a different IRQ each time, but the 2 devices are always
shared, eg

pci=noacpi -> 169: 5140 IO-APIC-level bttv0, uhci_hcd:usb1
pci=routeirq -> 153: 1253 IO-APIC-level bttv0, uhci_hcd:usb1

I guess there's no workaround for our problem. If there are any more
suggestions, please let me know, we hope the pci latency settings will
get us going for now.

Regards
Keith
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