From owner-freebsd-hackers  Mon Dec  7 14:19:38 1998
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id OAA24115
          for freebsd-hackers-outgoing; Mon, 7 Dec 1998 14:19:38 -0800 (PST)
          (envelope-from owner-freebsd-hackers@FreeBSD.ORG)
Received: from numeri.campus.luth.se (numeri.campus.luth.se [130.240.197.103])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id OAA24110
          for <hackers@FreeBSD.ORG>; Mon, 7 Dec 1998 14:19:35 -0800 (PST)
          (envelope-from k@numeri.campus.luth.se)
Received: from numeri.campus.luth.se (localhost [127.0.0.1])
	by numeri.campus.luth.se (8.8.8/8.8.8) with ESMTP id XAA03758;
	Mon, 7 Dec 1998 23:23:56 +0100 (CET)
	(envelope-from k@numeri.campus.luth.se)
Message-Id: <199812072223.XAA03758@numeri.campus.luth.se>
X-Mailer: exmh version 2.0.2 2/24/98
To: "Ron G. Minnich" <rminnich@Sarnoff.COM>
cc: hackers@FreeBSD.ORG
Subject: Re: write combining memory on pci 
In-reply-to: Your message of "Mon, 07 Dec 1998 15:48:33 EST."
             <Pine.SUN.3.91.981207154806.9378D-100000@terra> 
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Date: Mon, 07 Dec 1998 23:23:56 +0100
From: Johan Karlsson <k@numeri.campus.luth.se>
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by hub.freebsd.org id OAA24111
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

At Mon, 07 Dec 1998 15:48:33 EST, "Ron G. Minnich" wrote:
>any good ideas on how to turn this on in 3.0 for a given memory address 
>range? 
>

This can be done using the MTRRs (Memory Type Range Registers) on a Ppro or 
PII.

There are some functions in i386/i386/pmap.c to read and write those 
registers. (I don't know if the registers are enabled by default)
For more info about the registers see
http://www.intel.com/design/pro/manuals
chapter 9 in "Intel Architecture Software Developer's Manual, Volume 3: System 
Programming Guide"

Usualy the BIOS sets these registers. You can screw up the memory management 
bad if you don't know what you are doing.

Take small steps :-)

/Johan K

-- 
Johan Karlsson		mailto:k@numeri.campus.luth.se
SWEDEN



To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message