Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756722AbXEaO1i (ORCPT ); Thu, 31 May 2007 10:27:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752470AbXEaO1a (ORCPT ); Thu, 31 May 2007 10:27:30 -0400 Received: from shawidc-mo1.cg.shawcable.net ([24.71.223.10]:21280 "EHLO pd2mo3so.prod.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752110AbXEaO13 (ORCPT ); Thu, 31 May 2007 10:27:29 -0400 Date: Thu, 31 May 2007 08:27:27 -0600 From: Robert Hancock 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: To: Justin Piszcz Cc: Parag Warudkar , linux-kernel@vger.kernel.org, crmotherboard@intel.com Message-id: <465EDB4F.6020800@shaw.ca> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7bit References: <82e4877d0705301757v580a4ca5yebe2a565f0b97552@mail.gmail.com> <465E513E.60903@shaw.ca> <465EC464.7050302@gmail.com> User-Agent: Thunderbird 2.0.0.0 (Windows/20070326) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2005 Lines: 48 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/ - 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/