Date: 13 May 1998 09:43:23 +0200 From: dag-erli@ifi.uio.no (Dag-Erling Coidan =?iso-8859-1?Q?Sm=F8rgrav?= ) To: jjw@us.net Cc: "=?iso-8859-1?Q?=22Dag?= -Erling Coidan =?iso-8859-1?Q?Sm=F8rgrav=22?= <dag-erli@ifi.uio.no>=?iso-8859-1?Q?=2C?= Andrew Short" <dag-erli@ifi.uio.no>, stable@FreeBSD.ORG Subject: Re: PC Keyboard Ctrlr Chip (was: PPP hard lock in 2.2.6) Message-ID: <xzp3eeesjj8.fsf@hindarfjell.ifi.uio.no> In-Reply-To: John Woodruff's message of "Tue, 12 May 1998 18:34:26 -0400" References: <Pine.SUN.3.96.980512135132.23087D-100000@galileo.cris.com> <xzplns76zlv.fsf@hrotti.ifi.uio.no> <3558CE72.2300BB70@us.net>
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John Woodruff <jjw@us.net> writes: > Andrew Short <Ashort@concentric.net> 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
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