Date: Sun, 13 Aug 2000 02:20:04 -0700 (PDT) From: Johan Karlsson <k@numeri.campus.luth.se> To: freebsd-doc@freebsd.org Subject: Re: kern/17774: stray irq7 Message-ID: <200008130920.CAA06560@freefall.freebsd.org>
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The following reply was made to PR kern/17774; it has been noted by GNATS.
From: Johan Karlsson <k@numeri.campus.luth.se>
To: Bruce Evans <bde@zeta.org.au>
Cc: freebsd-gnats-submit@FreeBSD.ORG
Subject: Re: kern/17774: stray irq7
Date: Sun, 13 Aug 2000 11:11:55 +0200
At Sun, 13 Aug 2000 08:55:04 +1000, Bruce Evans wrote:
> On Fri, 11 Aug 2000, Johan Karlsson wrote:
>
> > I suggest the following is added to the faq
>
> The fwa? :-).
???
>
> > =============
> > Q: What does 'stray irq' mean?
> > A: Stray irq are interupts from some hardware that do not have
> > a driver assigned to it. J Wunsch writes in a response to a PR
>
> No, they are mostly from hardware that removes its interrupt request
> in the middle of the interrupt request acknowledge cycle. FreeBSD's
> interrupt handling (toggling the PIC masks at a critical time)
> probably amplifies this problem. Assigning a driver can "fix" the
> problem by breaking detection of it. The correct fix is to detect
> the stray interrupts caused by interrupt timing glitches and decide
> what to do about them (whatever is done, it shouldn't involve
> printing a faq magnet).
Ok
Should the print of this text be removed from kernel then?
Is the following suggestion for the FAQ better or should we not
have an FAQ entry at all for this (which I think we should since
the question pops up)?
============
Q: What does 'stray irq' mean?
A: Stray IRQs are indications of hardware IRQ glitches, mostly
from hardware that removes its interrupt request in the middle
of the interrupt request acknowledge cycle.
J Wunsch writes in a response to a PR
"Stray IRQs are a known phenomenon. Obviously (if you think about it :),
there's nothing the kernel could do about it. Unless you have
misconfigured your kernel so there's no driver assigned to a device
that actually issues IRQs, they are a sign of flakey hardware, often
caused by glitches on an IRQ line."
You have three choices:
1) Live with the warnings
2) Get a driver for the hardware into your kernel
3) Remove the hardware that generates the interrupts
=============
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