Re: APIC errors and aic7xxx interrupts w/SMP on 2.3.25

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Wed, 10 Nov 1999 09:57:29 +0100 (MET)

Doug Ledford wrote:
> On Tue, 9 Nov 1999 kumon@flab.fujitsu.co.jp wrote:
>
> > Another problem is on aic7xxx.
> >
> > /proc/interrupts saids the SCSI driver produces massive interrupts,
> > about 17000 interrupts per second for each CPU even if no SCSI
> > devices are attached.
> >
> > The SCSI I/F(2940UWD) is a dual channel SCSI adaptor, only one of the
> > channel produces interupts.
> >
> > This happens on 2.3.25 but not on 2.3.18.
> >
> > Does anybody tell me a clue?
>
> This most likely means something besides the aic7xxx is making that
> interrupt but as sson as the aic7xxx is loaded and that interrupt is
> enabled then the other device (whatever it may be, check the output of
> lspci to see if anything else is sharing that interrupt) is likely making
> all those interrupts and that's what needs fixed.

- The machine doesn't hang, so if it's a level triggered interrupt,
something must be disabeling the interrupt.

- It would've been pretty obvious to someone looking in
/proc/interrupts that the interrupt is shared.

- Could some device be holding hte interrupt line "active" for say 10%
of the time (without feedback from its driver!), and thus triggering
"short" interrupt storms?

If the interrupt indeed isn't shared, I would recommend enabelign
debugging on the AIC7xxx driver. This should tell you what the chip
thinks needs to be addressed. (I'm not familiar with the AIC driver,
so I don't know how much debugging it will spew at you from the
interrupt routine.)

Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
 "I didn't say it was your fault. I said I was going to blame it on you."


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