Re: Linux 2.6.20-rc6 - sky2 resume breakage

From: Ingo Molnar
Date: Wed Jan 31 2007 - 12:40:35 EST



* Jeff Garzik <jeff@xxxxxxxxxx> wrote:

> >ok. Can you suggest any way for me to reproduce such a bug
> >artificially on a test system? [i have both old and new systems, so
> >if you can think of a way for me to trigger this i'd be happy to try]
>
> Should be pretty easy. With either the old-IDE driver or libata,
> complete a command without acknowledging an interrupt. For libata,
> that means poking around in ata_host_intr() and avoiding well-built
> hardware like AHCI. Anything that uses ata_piix driver, basically all
> Intel machines, should be applicable in the "not well built"
> category... :)

ok, here's one victi^H^H^H^H testbox that seems to match your
description:

18: 3 0 IO-APIC-fasteoi uhci_hcd:usb3, ohci1394
19: 2413090 0 IO-APIC-fasteoi uhci_hcd:usb2, libata
22: 168 0 IO-APIC-fasteoi HDA Intel
23: 0 0 IO-APIC-fasteoi uhci_hcd:usb1, ehci_hcd:usb5

so i should try to generate some missing ACK [this meaning a missing
driver-level ack, right?] on IRQ#19's libata handler - and i should
expect a screaming interrupt? Or non-working USB? Or both?

[ i can hunt for other hardware if this doesnt look broken enough to you
:-) ]

Ingo
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