From owner-freebsd-amd64@FreeBSD.ORG Mon Oct 13 12:16:00 2008 Return-Path: Delivered-To: freebsd-amd64@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 62FF51065686 for ; Mon, 13 Oct 2008 12:16:00 +0000 (UTC) (envelope-from gary.jennejohn@freenet.de) Received: from mout3.freenet.de (mout3.freenet.de [IPv6:2001:748:100:40::2:5]) by mx1.freebsd.org (Postfix) with ESMTP id B58848FC15 for ; Mon, 13 Oct 2008 12:15:59 +0000 (UTC) (envelope-from gary.jennejohn@freenet.de) Received: from [195.4.92.24] (helo=14.mx.freenet.de) by mout3.freenet.de with esmtpa (ID gary.jennejohn@freenet.de) (port 25) (Exim 4.69 #65) id 1KpML7-0003yq-WF for freebsd-amd64@FreeBSD.org; Mon, 13 Oct 2008 14:15:57 +0200 Received: from mad62.m.pppool.de ([89.49.173.98]:29168 helo=ernst.jennejohn.org) by 14.mx.freenet.de with esmtpa (ID gary.jennejohn@freenet.de) (port 25) (Exim 4.69 #65) id 1KpML7-0002Hd-O5 for freebsd-amd64@FreeBSD.org; Mon, 13 Oct 2008 14:15:57 +0200 Date: Mon, 13 Oct 2008 14:15:56 +0200 From: Gary Jennejohn To: freebsd-amd64@FreeBSD.org Message-ID: <20081013141556.7b7a0806@ernst.jennejohn.org> X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; amd64-portbld-freebsd8.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Subject: how does the kernel go about mapping memory for amd64? X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: gary.jennejohn@freenet.de List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Oct 2008 12:16:00 -0000 I have a new mother board, a Gigabyte GA-MA78GPM-DS2H, which shows really weird behavior under FreeBSD when I have 4GB of memory and a PCI card plugged into it. With an Adaptec 29160 plugged in FreeBSD sees only 3GB and there is _no_ memory mapped above 4GB. This seems like a bug in the BIOS. With no PCI card plugged in FreeBSD sees memory mapped above 4GB and almost 4GB are available. Note that this board has graphics in the chipset (AMD 780G) which uses UMA (128 MB) for the video buffer. This behavior leads me to believe that FreeBSD is only using the memory mapping hints provided by the BIOS and is not sizing and mapping memory itself. Is that correct? --- Gary Jennejohn