Re: Linux 2.6.20-rc6 - sky2 resume breakage

From: Ingo Molnar
Date: Tue Jan 30 2007 - 03:10:15 EST



* 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]

I /think/ my two patches should automatically avoid the 'cap themselves'
effect you outlined: the absolutely worst case should be that we'll have
twice the IRQ rate of the optimal one - but no irq storm nor lost
interrupts should happen due to irq trigger type mismatches, ever - as
long as the basic mapping of device to IRQ is correct. [ I tried to push
to include this in v2.6.20 but i lost that argument ;-) ]

Ingo
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