*BSD News Article 16283


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Newsgroups: comp.os.386bsd.bugs
Path: sserve!newshost.anu.edu.au!munnari.oz.au!metro!ipso!runxtsa!bde
From: bde@runx.oz.au (Bruce Evans)
Subject: Re: ISA strayintr ff (with 386bsd-0.1-0.2.3)
Message-ID: <1993May20.000450.9792@runx.oz.au>
Organization: RUNX Un*x Timeshare.  Sydney, Australia.
References: <C6z3x1.1LK@raistlin.udev.cdc.com> <1t57ruINNn53@gap.caltech.edu> <explorer.737559856@tbird.cc.iastate.edu>
Date: Thu, 20 May 93 00:04:50 GMT
Lines: 23

In article <explorer.737559856@tbird.cc.iastate.edu> explorer@iastate.edu (Michael Graff) writes:
>In <1t57ruINNn53@gap.caltech.edu> glt@cco.caltech.edu (Greg Tanaka) writes:
>>...  For instance, in my case it was 
>>simply matter of configuring a lpt port for my parallel port card at irq 7..
>>not I get absolutely no stray interrupts...  
>
>This almost makes sense now...  I just started getting them, my roomate does
>not get them at all.  I use lpa, the interruptless driver, he uses the regular
>one, the lpt driver.

You always got them, but previous versions of 386BSD did not report them,
to reduce the number of bug reports from nervous newbies :-).

You still get them, but the printer driver is too stupid to report them.
All interrupt glitches cause IRQ 7's, so any device driver that uses
IRQ 7 is reponsible for handling them.  The consequences of ignoring
interrupt glitches range from none to a hung system.  Obviously they
don't matter in most cases.

Interrupt glitches are special cases of "stray" interrupts.  Other stray
interrupts are "impossible" because they are masked.
-- 
Bruce Evans  bde@runx.oz.au