Re: Linux 2.6.20-rc6 - sky2 resume breakage

[Jeff Garzik]

Ingo Molnar wrote:
> * Jeff Garzik <jeff@xxxxxxxxxx> wrote:
>
> > Easy to name an example, as they are pretty generic.  When sharing 
> > irqs -- usually ATA is configured to PCI native (IO-APIC-fasteoi) -- 
> > any interrupt storm causes the other devices sharing that irq to crap 
> > themselves (kernel turns off irq, suggests irqpoll, etc.)
>
> 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... :)

	Jeff



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