Re: VIA KT400 + Kernel 2.6.12 + IO-APIC + uhci_hcd = IRQ trouble
From: Alan Stern
Date: Mon Jul 25 2005 - 21:04:21 EST
On Tue, 26 Jul 2005, Michel Bouissou wrote:
> Le Lundi 25 Juillet 2005 22:44, Alan Stern a écrit :
> > Now that's strange. When you plug the high-speed device into the
> > integrated ports, which IRQ counter changes? Since nothing is using IRQ
> > 21, it should be disabled and its counter should remain constant. Does
> > this mean the interrupts show up on IRQ 19 (used by ehci-hcd), or do they
> > not show up at all (i.e., is the USB connection just being polled)?
> I assume it's IRQ 19.
> cat /proc/interrupts doesn't show IRQ21 at all when uhci isn't loaded.
As it shouldn't, since nothing is supposed to be using that IRQ.
> IRQ 19 being shared with 4 IDE controllers that controls my hard drives,
> that's hard to isolate interrupts counts due to USB activity from interrupts
> counts due to disks activity...
I was afraid you'd say that...
Natalie, that's all I can think of. Now it's up to you to invent a patch
Michel can try out, to show just where the IO-APIC code is going wrong.
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