2002-01-28 08:37:47

by Alex Davis

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Subject: I've stopped the 'Spurious interrupts on IRQ7'

I added the following line to /etc/lilo.conf

append = "parport=0x378,7"

and re-ran lilo. I also noticed that the 'ERR' field in
/proc/interrupts stays at 0, whereas before the mod it
was increasing.

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2002-01-28 08:49:09

by Denis Vlasenko

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Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'

On 28 January 2002 06:37, Alex Davis wrote:
> I added the following line to /etc/lilo.conf
>
> append = "parport=0x378,7"
>
> and re-ran lilo. I also noticed that the 'ERR' field in
> /proc/interrupts stays at 0, whereas before the mod it
> was increasing.

Do you have a printer? Try to boot while it is powered off.
WHAT is generating irq 7 now?

It is documented that interrupt controller will report irq 7 if it sees irq
but cannot determine what device sends it. That's exactly what's happening
when you see "spurious int" message.

You made kernel believe it's from printer. That does not cure the real
problem. BTW, there's not much of a problem, kernel just ignores spurious
interrupts. It _is_ a problem if you see 'ERR' number rapidly increasing.
--
vda

2002-01-28 11:55:22

by Rene Rebe

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Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'

Hi.

From: Denis Vlasenko <[email protected]>
Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'
Date: Mon, 28 Jan 2002 10:46:02 -0200

> On 28 January 2002 06:37, Alex Davis wrote:
> > I added the following line to /etc/lilo.conf
> >
> > append = "parport=0x378,7"
> >
> > and re-ran lilo. I also noticed that the 'ERR' field in
> > /proc/interrupts stays at 0, whereas before the mod it
> > was increasing.
>
> Do you have a printer? Try to boot while it is powered off.
> WHAT is generating irq 7 now?

Hi. As I stated before I get "Spurious interrupts on IRQ7" ony many
(all?) systems (from AMD-K62/Ali, over Pentium-II to AMD-K7-XP/SiS)
with the latest kernels. I started arround 2.4.14/15 ... - None system
has anything attached to the LPT port ...

I'll try to find some time to reboot some to see where it started ...

> It is documented that interrupt controller will report irq 7 if it sees irq
> but cannot determine what device sends it. That's exactly what's happening
> when you see "spurious int" message.
>
> You made kernel believe it's from printer. That does not cure the real
> problem. BTW, there's not much of a problem, kernel just ignores spurious
> interrupts. It _is_ a problem if you see 'ERR' number rapidly increasing.
> --
> vda

k33p h4ck1n6
Ren?

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2002-01-28 14:31:05

by Alex Davis

[permalink] [raw]
Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'


--- Denis Vlasenko <[email protected]> wrote:
> On 28 January 2002 06:37, Alex Davis wrote:
> > I added the following line to /etc/lilo.conf
> >
> > append = "parport=0x378,7"
> >
> > and re-ran lilo. I also noticed that the 'ERR' field in
> > /proc/interrupts stays at 0, whereas before the mod it
> > was increasing.
>
> Do you have a printer?
Yes.
> Try to boot while it is powered off.
Spurious ints. occur whether the printer is on of off.


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2002-01-28 14:40:20

by Rene Rebe

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Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'

From: Denis Vlasenko <[email protected]>
Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'
Date: Mon, 28 Jan 2002 14:19:13 -0200

> I'm not saying printer has anything to do with this. I'm saying that irq7 is

Yes. I know and understand what you said! ;-) I only added that it
might not be a hardware bug - but a miss-programming or interpreting
of the hardware, introduced in one of the last 2.4.1x kernel! I never
got this in the past and now I get it on ALL machnines!

Or was this debug-message introduced in a 2.4.x kernel and this
situation was simply ignored?

> not generated by LPT port in this case, it is interrupt controller saying:
> "I've got anonymous interrupt request". Shouldn't happen, it's minor hw bug.
>
> With "parport=0x378,7" kernel thinks that it's printer and hence don't emit
> "spurious int" msg. I bet if you look in parport code you'll see that LPT
> ints get silently ignored if there's nothing to do. It just thinks: "whee,
> printer int, let's look at LPT ports... hmm, strange, printer is ready,
> nothing to do... oh well, iret".
> --
> vda

k33p h4ck1n6
Ren?

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2002-01-29 14:16:12

by Maciej W. Rozycki

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Subject: Re: I've stopped the 'Spurious interrupts on IRQ7'

On Mon, 28 Jan 2002, Rene Rebe wrote:

> Or was this debug-message introduced in a 2.4.x kernel and this
> situation was simply ignored?

The message was introduced during the 2.3.x development cycle.

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
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