RE: Kernel 2.6.12 + IO-APIC + uhci_hcd = Trouble

[Protasevich, Natalie]

> > On the other hand, _something_ was generating an interrupt request 
> > that got mapped to IRQ 21 by the hardware.  And these 
> requests do seem 
> > to be associated with USB activity.  Maybe the EHCI 
> controller is responsible?
> > One of your postings showed both uhci_hcd:usb2 and ehci_hcd:usb4 
> > mapped to IRQ 11.  That could indicate a shared signal 
> line, which is 
> > currently being mapped incorrectly.

I suspect that some device is actually on the IRQ 21, and that's how its IO-APIC line is set up. Later on, its driver tries to assign different IRQ, due to some discrepancy, and the handler gets registered on say IRQ 11, and to a wrong pin, so the actual interrupts go unattended. If this what's happening, the trace will hopefully tell the story. I suggest to boot with "apic=debug" and also perhaps with "pci=routeirq" and collect the trace. You can attach the part up to the point when it reports usb devices set up. 

--Natalie

 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/