Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761640AbXEaSoU (ORCPT ); Thu, 31 May 2007 14:44:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755215AbXEaSoK (ORCPT ); Thu, 31 May 2007 14:44:10 -0400 Received: from lucidpixels.com ([75.144.35.66]:36275 "EHLO lucidpixels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757384AbXEaSoJ (ORCPT ); Thu, 31 May 2007 14:44:09 -0400 Date: Thu, 31 May 2007 14:44:07 -0400 (EDT) From: Justin Piszcz X-X-Sender: jpiszcz@p34.internal.lan To: Robert Hancock cc: Parag Warudkar , linux-kernel@vger.kernel.org, crmotherboard@intel.com Subject: Re: Case: 7454422: Re: Kernel 2.6.21.3 does not work with 8GB of RAM on Intel 965WH motherboards. (FULL DMESG) In-Reply-To: <465EDB4F.6020800@shaw.ca> Message-ID: References: <82e4877d0705301757v580a4ca5yebe2a565f0b97552@mail.gmail.com> <465E513E.60903@shaw.ca> <465EC464.7050302@gmail.com> <465EDB4F.6020800@shaw.ca> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2554 Lines: 60 On Thu, 31 May 2007, Robert Hancock wrote: > Justin Piszcz wrote: >> On Thu, 31 May 2007, Parag Warudkar wrote: >> >>> Robert Hancock wrote: >>>> I think that mem=8832M would work as well, to make the kernel use only >>>> the memory that is marked cacheable. (It looks like this parameter takes >>>> the highest memory address we want the kernel to use, not the highest >>>> memory amount.) >>>> >>> Yep, and that would be much easier too. >>> >>> I am curious though as this seems to be somewhat common a problem, could >>> we make the kernel analyze which memory is not cacheable (it already knows >>> this via MTRR) and not use that portion for anything? Plus may be warn the >>> user to contact their BIOS vendor to correct the problem? >>> >>> I think that would be possible - even if the kernel knows late that the >>> memory was uncached we could migrate those pages in that region to >>> someplace else? >>> >>> Parag >>> >> >> That is an excellent question and I wonder the same thing. I also had this >> problem when I only used 4GB of ram and upgraded the (another motherboard, >> I have two) past version 1666P and I had no idea what was going on other >> than the BIOS did not work correctly. >> >> In this case however it worked with 4GB with bios version 1612P but not >> with 8GB. Is this the case of a buggy BIOS for the 965 chipset or do Intel >> boards have a lot of issues? > > We could conceivably generate a warning if the MTRRs don't map all of the > physical memory as write-back. Actually, conceivably we could actually go and > fix up the MTRRs if we found them to be wrong according to the E820 memory > map. That would be more complicated, however. > > -- > Robert Hancock Saskatoon, SK, Canada > To email, remove "nospam" from hancockr@nospamshaw.ca > Home Page: http://www.roberthancock.com/ > Intel is working on a work-around/fix for this problem, they said I need to wait another day or so until it is completed. I will let everyone know what the outcome is, hopefully it is a good fix :) I totally agree however, a lot of 'weird' problems that some people may attribute to Linux are actually BIOS problems, I think warnings in the kernel would be a good idea, then they would not have to blame the kernel for BIOS issues :) Justin. - 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/