Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752521AbXF3BIN (ORCPT ); Fri, 29 Jun 2007 21:08:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751202AbXF3BIB (ORCPT ); Fri, 29 Jun 2007 21:08:01 -0400 Received: from z2.cat.iki.fi ([212.16.98.133]:49843 "EHLO z2.cat.iki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751190AbXF3BIA (ORCPT ); Fri, 29 Jun 2007 21:08:00 -0400 Date: Sat, 30 Jun 2007 04:08:22 +0300 From: Matti Aarnio To: Frank Fiene Cc: linux-kernel@vger.kernel.org, tytso@thunk.org Subject: Re: Kernel doesn't recognize complete memory Message-ID: <20070630010822.GP4504@mea-ext.zmailer.org> References: <200706292225.26503.ffiene@veka.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200706292225.26503.ffiene@veka.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1667 Lines: 44 On Fri, Jun 29, 2007 at 10:25:26PM +0200, Frank Fiene wrote: > Lenovo Z61p, Intel Core2 Duo T7200 > > I have 4GB RAM installed and BIOS recognize 4GB RAM. > Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2 32bit-PAE > and 64bit) tells me: only 3GB of RAM are installed. With AMD's Athlon64 the answer would be "look into BIOS settings, (re)map 3-4 GB memory above 4 GB address mark".. The PCI-bus and all IO devices in it needs memory space within the first 4 GB of physical address space. Some devices support 64-bit addresses in which case they can access whole physical memory, most probably don't, meaning that they can access only memory in lowest 4 GB part of the space. Original 8088 PC had 20 bit address space, and "huge" megabyte of address space. Then came 286 AT era with 24 bit addresses and "whopping" 16 megabyte address space.. then came 386 and finally true 32-bit addresses -- but ISA-space VGA aperture had to be in there still.. and to gain access to of that memory located "under" that VGA aperture, there was mapping... Now the VGA aperture mapping is no more, but the PCI has similar requirements - albeit with bigger apertures. So, what does your BIOS have hidden in "advanced" menus (most likely) ? Something about "remap (PCI?) memory above 4 GB" ? > Any other user with a 4GB Thinkpad? tytso? > > What can i do? Please help! > > Regards > Frank Regards, Matti Aarnio - 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/