From: Gunther.Mayer@t-online.de (Gunther Mayer)
To: root@chaos.analogic.com
Cc: Chris Meadors <clubneon@hereintown.net>,
Martin Eriksson <nitrax@giron.wox.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
martin@jtrix.com
Subject: Re: 'spurious 8259A interrupt: IRQ7' -> read the 8259 datasheet !
Date: Fri, 30 Nov 2001 20:28:06 +0100 [thread overview]
Message-ID: <3C07DDC6.5FAE4E35@t-online.de> (raw)
In-Reply-To: <Pine.LNX.3.95.1011128084801.10732A-100000@chaos.analogic.com>
"Richard B. Johnson" wrote:
>
> On Wed, 28 Nov 2001, Chris Meadors wrote:
>
> > On Wed, 28 Nov 2001, Martin Eriksson wrote:
...
... rumours deleted (e.g. "printer status bits are all ORed into irq7")
...
>From "Harris Semiconductor 82C59A Interrupt Controller Datasheet":
If no interrupt request is present at step 4 of either sequence
(i.e., the request was too short in duration), the 82C59A will
issue an interrupt level 7.
1. The irq controller sees an interrupt.
2. The irq controller signals "there is _some_ interrupt" to the cpu.
3. The CPU acks via INTA
4. The irq controller looks if the irq is still there
(and signals IRQ7 if the line is no longer active).
You have some device which doesn't keep the IRQ raised long enough !
(or the CPU doesn't service the irq for a too long time and the
edge triggered irq is de-asserted or even serviced by a polling routine)
next prev parent reply other threads:[~2001-11-30 19:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-27 17:06 'spurious 8259A interrupt: IRQ7' Alex Davis
2001-11-28 0:01 ` Peter Bornemann
2001-11-28 8:58 ` szonyi calin
2001-11-28 9:31 ` Wouter van Bommel
2001-11-28 9:52 ` Martin Eriksson
2001-11-28 13:59 ` Chris Meadors
2001-11-28 14:06 ` Richard B. Johnson
2001-11-28 14:23 ` Piter Punk
2001-11-30 19:28 ` Gunther Mayer [this message]
2001-11-30 19:47 ` 'spurious 8259A interrupt: IRQ7' -> read the 8259 datasheet ! Richard B. Johnson
2001-11-30 22:44 ` Gunther Mayer
2001-11-30 20:14 ` Martin Eriksson
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