Re: NForce2 pseudoscience stability testing (2.6.0-test11) - IRQ flood related ?

From: Jesse Allen
Date: Thu Dec 04 2003 - 17:59:13 EST

On Thu, Dec 04, 2003 at 09:02:08PM +0100, cheuche+lkml@xxxxxxx wrote:
> Hello,
> Along with the lockups already described here, I've noticed an
> unidentified source of interrupts on IRQ7.
> I wonder if people experiencing lockup problems also have these
> noise interrupts,

I just took a look at this, by setting up parport_pc, and yes I get noise.

This was my first sample with a kernel with APIC:
7: 29230 IO-APIC-edge parport0

Then I took a look again about 5 seconds later:
7: 41560 IO-APIC-edge parport0

And I looked again, and it was higher. If you take a look repeatally, you see
it increases for 2-3 seconds, then stops for 2-3, then starts increasing again
and continues like this. This is pretty much an idle system other than me
cat'ing. I'm not using the parallel port at all.

Then I looked at the irq with parport_pc setup and with a kernel with APIC all
7: 0 XT-PIC parport0

And it is the same on repeated cat's.

These kernels are exactly the same except ones compiled with UP APIC and the
other isn't. I don't know how parport works, but seeing two different events
under this condition does seem suspicious.

> and I don't know if this has something to do with the
> lockups or if it is an independant problem.

I have no idea, but it is suspicious, as I get lockups and this noise with the
APIC enabled kernel.

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