From owner-freebsd-stable Wed May 13 00:43:38 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id AAA02504 for freebsd-stable-outgoing; Wed, 13 May 1998 00:43:38 -0700 (PDT) (envelope-from owner-freebsd-stable@FreeBSD.ORG) Received: from ifi.uio.no (0@ifi.uio.no [129.240.64.2]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id AAA02459 for ; Wed, 13 May 1998 00:43:24 -0700 (PDT) (envelope-from dag-erli@ifi.uio.no) Received: from hindarfjell.ifi.uio.no (2602@hindarfjell.ifi.uio.no [129.240.64.130]) by ifi.uio.no (8.8.8/8.8.7/ifi0.2) with ESMTP id JAA25629; Wed, 13 May 1998 09:43:24 +0200 (MET DST) Received: (from dag-erli@localhost) by hindarfjell.ifi.uio.no ; Wed, 13 May 1998 09:43:23 +0200 (MET DST) Mime-Version: 1.0 To: jjw@us.net Cc: "=?iso-8859-1?Q?=22Dag?= -Erling Coidan =?iso-8859-1?Q?Sm=F8rgrav=22?= =?iso-8859-1?Q?=2C?= Andrew Short" , stable@FreeBSD.ORG Subject: Re: PC Keyboard Ctrlr Chip (was: PPP hard lock in 2.2.6) References: <3558CE72.2300BB70@us.net> Organization: University of Oslo, Department of Informatics X-url: http://www.stud.ifi.uio.no/~dag-erli/ X-Stop-Spam: http://www.cauce.org From: dag-erli@ifi.uio.no (Dag-Erling Coidan =?iso-8859-1?Q?Sm=F8rgrav?= ) Date: 13 May 1998 09:43:23 +0200 In-Reply-To: John Woodruff's message of "Tue, 12 May 1998 18:34:26 -0400" Message-ID: Lines: 35 X-Mailer: Gnus v5.5/Emacs 19.34 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by hub.freebsd.org id AAA02469 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk John Woodruff writes: > Andrew Short writes: > > My (I use it at work, I am not lucky enough to OWN one!) > > Sun UltraSparc has a feature that will arrest control from the > > OS by doing a Stop-A on the keyboard. > > Dag-Erling Coidan Smørgrav wrote: > > [...] There is no way to do this on a PC, unless some bright > > motherboard vendor somes up with the idea of producing a motherboard > > that e.g. drops to a BIOS prompt when the keyboard controller (i8042) > > asserts the reset pin [...] > > > > I tried to find information about the 8042 on Intel's web site, but > > there doesn't seem to be any (except for references to it in chipset > > or motherboard datasheets). > > The 8042 is a general-purpose single-chip computer/controller; which > has been used since the dawn of time (or at least of the IBM PC/AT) Yup, the original PC and XT used the 8048. I know all that... what I was looking for was programming information - I know that outputting 0xfe to port 0x64 makes the 8042 assert the reset pin on the CPU, but I want to know *why* :) > Seems odd, but AFAIK the standard program has no way of triggering > the CPU reset on command from the keyboard - the main CPU has to > *ask* to be reset, which is why Ctrl-Alt-Del does nothing to a > hard-locked (or -looping) CPU. It shouldn't really be a problem to design a keyboard with this possibility. -- Noone else has a .sig like this one. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message