Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761546AbXFDTXe (ORCPT ); Mon, 4 Jun 2007 15:23:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758829AbXFDTX0 (ORCPT ); Mon, 4 Jun 2007 15:23:26 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39324 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756799AbXFDTXZ (ORCPT ); Mon, 4 Jun 2007 15:23:25 -0400 Date: Mon, 4 Jun 2007 21:23:23 +0200 From: Andi Kleen To: Justin Piszcz Cc: "Eric W. Biederman" , Jesse Barnes , Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: Intel's response Linux/MTRR/8GB Memory Support / Why doesn't the kernel realize the BIOS has problems and re-map appropriately? Message-ID: <20070604192323.GA14844@one.firstfloor.org> References: <200706011407.51779.jbarnes@virtuousgeek.org> <20070601211943.GO7217@one.firstfloor.org> <200706011441.57149.jbarnes@virtuousgeek.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1594 Lines: 35 > From their e-mail: > > Note before continuing: Debian* Linux Operating System is not an > officially, validated, tested Operating System for the Intel(R) Desktop > Board DG965WH > (see http://downloadcenter.intel.com/Product_Filter.aspx?ProductID=2375); > moreover, we do confirm that "on a system that has 8 GB of system memory > installed, it is not possible to use all of the installed memory due to > system address space being allocated for other system critical functions." > [qtd. on page 43 of the Technical Product Specification (see > http://download.intel.com/design/motherbd/wh/D5600801US.pdf)]. Thus, the > following suggestions are provided AS IS; we cannot guarantee the problem > would be fixed afterwards: They're talking about something different than your issue. If you put in the fully possible 8GB (4x2GB) then some memory will be lost to the PCI hole because the desktop ICH can only access 35bits (8GB) in hardware. That can be up to 2GB in extreme cases, usually <0.5-1GB depending on how much mapping space your hardware needs. But if you put in less than 8GB the BIOS is supposed to remap the memory around the PCI hole and set up the MTRRs correctly so that the PCI hole is uncached and the memory around it is cached. That is 100% the BIOS' responsibility and if it doesn't do that it is buggy. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/