From: "Petr Vandrovec" <VANDROVE@vc.cvut.cz>
To: Chris Wedgwood <cw@f00f.org>
Cc: swsnyder@home.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
alan@lxorguk.ukuu.org.uk
Subject: Re: "APIC error on CPUx" - what does this mean?
Date: Mon, 7 Jan 2002 14:16:28 +0100 [thread overview]
Message-ID: <E37DB7922B4@vcnet.vc.cvut.cz> (raw)
On 8 Jan 02 at 2:08, Chris Wedgwood wrote:
> On Mon, Jan 07, 2002 at 01:29:42PM +0100, Petr Vandrovec wrote:
>
> They are spurious IRQ 7, just message is printed only once during
> kernel lifetime... I have about three spurious IRQ 7 per each 1000
> interrupts delivered to CPU. It is on A7V (Via KT133).
>
> Any idea _why_ these occur though? It seems some mainboards produce a
> plethora of these whilst others never produce these...
Nope. Probably when CPU is in local APIC mode, it acknowledges interrupts
to chipset with different timming, and from time to time CPU still
sees IRQ pending, so it asks for vector, but as chipset has no
interrupt pending, it answers with IRQ7. I did no analysis to find
whether IRQ7 happens directly when we send confirmation to 8259,
or whether it happens due to some noise on IRQ line.
AFAIK it happens only on VIA based boards, and only if (AMD) CPU is using
APIC.
Best regards,
Petr Vandrovec
vandrove@vc.cvut.cz
next reply other threads:[~2002-01-07 13:17 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-07 13:16 Petr Vandrovec [this message]
2002-01-07 13:33 ` "APIC error on CPUx" - what does this mean? Alan Cox
2002-01-07 13:42 ` Chris Wedgwood
2002-01-07 14:40 ` Martin Eriksson
2002-01-07 17:32 ` Steven Walter
2002-01-07 18:20 ` Rene Rebe
-- strict thread matches above, loose matches on Subject: below --
2002-01-09 12:41 Petr Vandrovec
2002-01-09 14:34 ` Maciej W. Rozycki
2002-01-08 17:35 Petr Vandrovec
2002-01-07 16:58 Petr Vandrovec
2002-01-08 12:12 ` Maciej W. Rozycki
2002-01-08 12:30 ` Chris Wedgwood
2002-01-07 12:29 Petr Vandrovec
2002-01-07 13:08 ` Chris Wedgwood
2002-01-03 19:55 Steve Snyder
2002-01-03 20:10 ` listmail
2002-01-03 21:47 ` Ryan Cumming
2002-01-03 22:38 ` Alan Cox
2002-01-03 23:21 ` Pozsar Balazs
2002-01-07 10:17 ` Chris Wedgwood
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