Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268089AbUIPOM7 (ORCPT ); Thu, 16 Sep 2004 10:12:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268086AbUIPOMU (ORCPT ); Thu, 16 Sep 2004 10:12:20 -0400 Received: from merkurneu.hrz.uni-giessen.de ([134.176.2.3]:33730 "EHLO merkurneu.hrz.uni-giessen.de") by vger.kernel.org with ESMTP id S268083AbUIPOJ5 (ORCPT ); Thu, 16 Sep 2004 10:09:57 -0400 Date: Fri, 17 Sep 2004 00:09:51 +1000 (EST) From: Sergei Haller X-X-Sender: gc1007@fb07-calculator.math.uni-giessen.de To: Andrew Walrond Cc: linux-kernel@vger.kernel.org Subject: Re: lost memory on a 4GB amd64 In-Reply-To: <200409161448.39033.andrew@walrond.org> Message-Id: References: <200409161448.39033.andrew@walrond.org> Organization: University of Giessen * Germany MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-HRZ-JLUG-MailScanner-Information: Passed JLUG virus check X-HRZ-JLUG-MailScanner: Found to be clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2544 Lines: 74 On Thu, 16 Sep 2004, Andrew Walrond (AW) wrote: AW> On Thursday 16 Sep 2004 05:48, Sergei Haller wrote: AW> > Hello, AW> > AW> > A friend of mine has a new Opteron based machine (Tyan Tiger K8W with two AW> > Opteron 24?) and 4GB main memory. AW> AW> Typo? Tyan Thunder? no, it's a tiger: http://www.tyan.com/products/html/tigerk8w.html AW> > the problem is that about 512 MB of that memory is lost (AGP aperture and AW> > stuff). Although everything is perfect otherwise. AW> > As far as I understand, all the PCI/AGP hardware uses the top end of the AW> > 4GB address range to access their memory and there is just an AW> > "overlapping" of the addresses. thus only the remaining 3.5 GB are AW> > available. AW> > AW> > AW> > Now there is an option in the BIOS called "Adjust Memory" which puts a AW> > certain amount of memory (several choices between 64MB and 2GB) above the AW> > 4GB address range. I tried the 2GB setting which results in 2GB main AW> > memory at addresses 0-2GB and 2GB memory at addresses 4GB-6GB. AW> > AW> AW> Ok; AW> AW> Assuming bios version 2.02. yes AW> The option you mention should be set to 'Auto' AW> AW> Chipset->Northbridge->Memory Configuration->Adjust Memory = Auto AW> AW> but set AW> AW> Advanced->Cpu Configuration->MTRR Mapping = Continuous I had "MTRR Mapping = Continuous" set all the time and tried "Adjust Memory" in all three modes (Auto/manual/disabled) and manual with 1 and 2gb size. today I had discovered the MTRR option and changed it to "discrete". tried "Adjust Memory" manually at 2gb. the only working (but with loss of memory) combination seems to be "Adjust Memory = disabled" and independant of "MTRR Mapping". The only combination I didn't try is "MTRR Mapping=Discrete"+"Adjust Memory= Auto". Will try tomorrow morning. AW> That fixed it for me if I remember correctly :) do you have a thunder or a tiger? And could you check in your BIOS setup whih options you used? thanks, Sergei -- -------------------------------------------------------------------- -?) eMail: Sergei.Haller@math.uni-giessen.de /\\ -------------------------------------------------------------------- _\_V Be careful of reading health books, you might die of a misprint. -- Mark Twain - 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/