Date: Sat, 24 Oct 1998 22:00:52 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: phk@critter.freebsd.dk (Poul-Henning Kamp) Cc: tlambert@primenet.com, dwhite@resnet.uoregon.edu, jeff-ml@mountin.net, freebsd-current@FreeBSD.ORG Subject: Re: 3.0 missing some docs? Message-ID: <199810242200.PAA25750@usr01.primenet.com> In-Reply-To: <6537.909182675@critter.freebsd.dk> from "Poul-Henning Kamp" at Oct 24, 98 00:44:35 am
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> >> It's a hardware-ism. IRQ 7 is the generic junk IRQ. > > > >I was under the impression that we had registered default handlers for > >all IRQ's, and thus 7 was no longer the grabage bin unless there > >was a deassert race that indicates a real problem? > > > >You should ask Bruce Evans for confirmation. > > IRQ is the i8259's garbage bin, regardless of config. If an IRQ is asserted > too short for classification by the i8259 it becomes irq7. Yeah; that's the race. I remember that when IRQ 2 was disabled in the interrupt controller, back before there were default handlers to catch and ack it if it were enabled, EGA cards with vertical retrace interrupt on IRQ 2 (for light pen support) used to get thrown onto 7 as "masked, unclassifiable". I think I remember something about unsupported portions of some sound cards throwing spurious interrupts with an open collector microphone input without a hold-down resistor, too. Anyway, my point is that it's much less "generic junk" now, and it probably indicates a real problem with some hardware that's asserting and then deasserting some other IRQ: in other words, there's some bad hardware on board that machine, it's not just an unexpected (but valid) interrupt from good hardware. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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