From owner-freebsd-hackers Mon Dec 7 14:07:40 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id OAA22631 for freebsd-hackers-outgoing; Mon, 7 Dec 1998 14:07:40 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from ceia.nordier.com (m2-27-dbn.dial-up.net [196.34.155.91]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id OAA22614 for ; Mon, 7 Dec 1998 14:07:34 -0800 (PST) (envelope-from rnordier@nordier.com) Received: (from rnordier@localhost) by ceia.nordier.com (8.8.7/8.6.12) id AAA01520; Tue, 8 Dec 1998 00:05:53 +0200 (SAT) From: Robert Nordier Message-Id: <199812072205.AAA01520@ceia.nordier.com> Subject: Re: How could this work? In-Reply-To: <199812072032.NAA05466@harmony.village.org> from Warner Losh at "Dec 7, 98 01:32:18 pm" To: imp@village.org (Warner Losh) Date: Tue, 8 Dec 1998 00:05:45 +0200 (SAT) Cc: rnordier@nordier.com, hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL31 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Warner Losh wrote: > In message <199812072031.WAA00262@ceia.nordier.com> Robert Nordier writes: > : IIRC, reads and writes involving port 0xb2 are done for their > : side-effects (to cause an SMI, put CPU into sleep mode, etc). > > I guess I'm asking how this happens? Can you provide more details, or > a pointer to same? Any read from the APM control register (port 0xb2 for certain chipsets) causes STPCLK# to be asserted, and the CPU goes into Stop-Grant State, from where it can enter Sleep State or return to Normal State. The Pentium II Processor Developer's Manual, Chapter 7, covers SMI#, STPCLK#, SLP#, etc; and there's a description of SMM in Vol. III of the Intel Architecture Software Developer's Manual. (Both available in acrobat format at the Intel web site literature center.) -- Robert Nordier To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message