From - Thu Oct 02 10:41:03 1997
Path: news.mitre.org!blanket.mitre.org!news.tufts.edu!cam-news-feed5.bbnplanet.com!cam-news-hub1.bbnplanet.com!news.bbnplanet.com!news.maxwell.syr.edu!news-peer.sprintlink.net!news.sprintlink.net!Sprint!newsfeed.internetmci.com!199.201.128.9!news.silcom.com!news.genuity.net!not-for-mail
From: Chris_Budd@inter-tel.com
Newsgroups: comp.os.ms-windows.programmer.nt.kernel-mode
Subject: NT, x86, NMI (IOCHCHK on ISA)
Date: Wed, 01 Oct 1997 21:55:31 GMT
Organization: Genuity Inc.  Phoenix, AZ
Lines: 38
Message-ID: <3432c6ac.189648640@news.genuity.net>
NNTP-Posting-Host: 192.68.180.123
X-Newsreader: Forte Free Agent 1.1/32.230

I have been trying to use the NMI interrupt (IOCHCHK on the ISA bus,
pin A1) on an x86 running WinNT 4.0 (no service packs).

My question now focuses on the return from this NMI interrupt handler;
I cannot seem to IRETD correctly back into the normal loop that was
interrupted by the NMI interrupt.  I even copied much of the code from
NT's NMI handler (KiTrap02) so that I mark my Task State Segment as
nonbusy, the previous TSS as busy, set the Nested Task Flags, etc.  I
always seem to get an unhandled or unexpected exception upon executing
my IRETD instruction; however, NT's IRETD never gets executed as the
code generates a blue screen with the NMI information.

I have searched the NT DDK, the Web, and the NT Dev archives (where I
found the following post).  I have read through a couple chapters on
interrupts in 386 books, and Custer's Inside NT; in addition I have
read the Dr. Dobbs article (May 1996 by Dale Roberts) on doing Direct
I/O from the application level in NT, which gave me some hope of
actually "hooking" this interrupt out from underneath NT.  I also
searched for NMI in the WDM  DDK (from WinHEC April 1997) and the
Win95 DDK.

In the Win95 DDK I was surprised to find what appeared to be routines
(e.g., Hook_NMI_Event) for drivers to chain onto the NMI interrupt.
However, nothing of the sort is in the WinNT DDK or WDM DDK.

1.)  Does anyone use this IOCHCHK pin (NMI) on the ISA bus in either
Win95 or WinNT?

2.)  Does anyone know anything else I can try in my NMI handler to
return to the Task that the NMI interrupted?

3.)  Does anyone know anything else on x86/NT platform that could wake
up a "dead" machine?

Thanks in advance,
An NMI-Frustrated Chris.