Re: Debugging with NMI

Jeff Merkey (jmerkey@timpanogas.com)
Tue, 13 Jul 1999 15:40:28 -0600

This used to work on the older systems. Newer systems that use PCI bridge
circuitry don't let you do this because you form a local ground loop when
you short the pins, and they've got pull up and pull down logic that will
shunt the signal (the system sees it as a short and not an NMI) . Even NMI
cards won't work on most systems newer than about 96 that use the newer
Intel design.

Good luck.

Jeff

----- Original Message -----
From: Bryn Paul Arnold Jones <bpaj@gytha.demon.co.uk>
To: <borislav@ensim.com>
Cc: <linux-kernel@vger.rutgers.edu>
Sent: Tuesday, July 13, 1999 3:27 PM
Subject: Re: Debugging with NMI

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> On Tue, 13 Jul 1999 borislav@ensim.com wrote:
>
> > In article <fa.e66dv0v.1ch8vqe@ifi.uio.no> you wrote:
> > > On an ISA bus machine, if you short out the A1 and B1 pins of an ISA
> > > slot you will generate an NMI to the CPU. This interrupts even a
> >
> > I tried this and nothing happened (the machine is still up, no extra
> > output, cat /proc/interrupts says NMI: 0). I'm sure I used the correct
> > pins and the right type of paper clip. Any idea what else I might be
> > doing wrong?
> >
>
> Your problem is a plug'n'play(tm) paperclip, luckily almost all the
> plug'n'play(tm) material is in the surface of the wire. All you need to
> do is sandpaper the paperclip to remove the pnp coating and try again.
>
> The totally plug'n'play paperclips are easy to spot as after a few seconds
> of vigorous rubbing, a large ammount of the paperclip will have worn away.
>
> Please note any "rough hard surface"(tm) will do, as no manufactures of
> rough hard surfaces have managed to manufacture a pnp surface coating
> which is hard wearing enough to withstand the normal wear and tear which
> rough hard surfaces are subject to, and as we know to make the whole
> "rough hard surface"(tm) pnp is still too expensive.
>
> Bryn
> - --
> Or words to that effect ...
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