Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762406AbXFEAy6 (ORCPT ); Mon, 4 Jun 2007 20:54:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754168AbXFEAyv (ORCPT ); Mon, 4 Jun 2007 20:54:51 -0400 Received: from wa-out-1112.google.com ([209.85.146.183]:39287 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753822AbXFEAyu (ORCPT ); Mon, 4 Jun 2007 20:54:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=sqTMvya4m3oHZGQNhMWEE04uxwBDifxi4t7bK8/5N8TAKzm2PKeRSJ8Li20eqtu5xAOwN6zUMYnevPedvTDpUkRdfyUaUkFb3svI/52wOB+35VoOwIGIa+leXn9YrFCucFuwZy91u+/MrCdDsgl7DIjM02VdVHUulYM5+waaeW4= Message-ID: <86802c440706041754h2d7fe950ge5ea4c41146bdf97@mail.gmail.com> Date: Mon, 4 Jun 2007 17:54:46 -0700 From: "Yinghai Lu" To: "Andi Kleen" Subject: Re: Intel's response Linux/MTRR/8GB Memory Support / Why doesn't the kernel realize the BIOS has problems and re-map appropriately? Cc: "Justin Piszcz" , "Eric W. Biederman" , "Jesse Barnes" , linux-kernel@vger.kernel.org In-Reply-To: <20070604192323.GA14844@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200706011407.51779.jbarnes@virtuousgeek.org> <20070601211943.GO7217@one.firstfloor.org> <200706011441.57149.jbarnes@virtuousgeek.org> <20070604192323.GA14844@one.firstfloor.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1768 Lines: 38 On 6/4/07, Andi Kleen wrote: > > 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. then the BIOS need to disable mem remap to make thing simple if there 8G ram installed. YH - 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/