Subject: Re: ISA interrupt sharing
To: Mike Wlodarczyk <>
From: Rick Byers <>
List: port-i386
Date: 11/04/2000 15:21:01
Given that some boards do presumably support sharing their edge triggered
interrupts (although I've never seen one myself), I think the only
solution is to make this a compile-time option.  It would be trivial to
add a "ISAPNP_NOIRQSHARE_EDGE" option (infact I did just that back on
NetBSD-1.3).  Does anyone have any objection to such an option being
added?  If I submitted a patch ASAP is there any chance the option could
get added for 1.5?  This appears to be a common problem, it would be nice
to have a simple solution for the average user...


 On Sat, 4 Nov 2000, Mike Wlodarczyk wrote:

> Date: Sat, 4 Nov 2000 10:33:11 -0800
> From: Mike Wlodarczyk <>
> To:,
> Subject: ISA interrupt sharing
> Hello,
> I recently installed a second ISAPNP card (a WSS compatible sound
> card) in one of my i386 boxes and rediscovered why I was using the
> ISAPNP_ALLOC_INTR_MASK hack. After rebuilding a kernel [1] with
> wss audio support, when the kernel device probes where done, the
> sound card was allocated IRQ 5, the same as the ISAPNP modem and
> neither would then work. The cause of all of this, and the reason
> I was using ISAPNP_ALLOC_INTR_MASK, is that the code in
> sys/arch/i386/isa/isa_machdep.c allows edge triggered ISA
> interrupts to be shareable.
> Since there are several open PR's [2] which describe this same
> problem, I'm curious whether this issue can be resolved,
> perferably for 1.5.  Simply making IST_EDGE interrupts unshareable
> does indeed do the right thing on my system as well.
> Comments ?
> [1]
> NetBSD 1.5_BETA (AVERNUS) #1: Sun Oct 29 12:25:24 PST 2000
> root@avernus:/usr/src/sys/arch/i386/compile/AVERNUS
> [2] port-i386/6642, port-i386/7331, port-i386/8302
> --
> Mike Wlodarczyk

Rick Byers
University of Waterloo, Computer Science