From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263171AbTESWqP (ORCPT ); Mon, 19 May 2003 18:46:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263208AbTESWqP (ORCPT ); Mon, 19 May 2003 18:46:15 -0400 Received: from holomorphy.com ([66.224.33.161]:46057 "EHLO holomorphy") by vger.kernel.org with ESMTP id S263171AbTESWqN (ORCPT ); Mon, 19 May 2003 18:46:13 -0400 Date: Mon, 19 May 2003 15:59:04 -0700 From: William Lee Irwin III To: Timothy Miller Cc: Linux Kernel Mailing List Subject: Re: PCI mapping on large memory 32-bit machines Message-ID: <20030519225904.GI8978@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Timothy Miller , Linux Kernel Mailing List References: <3EC91F3B.8010005@techsource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3EC91F3B.8010005@techsource.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 19, 2003 at 02:15:23PM -0400, Timothy Miller wrote: > On x86 with PAE and 4 gigs of RAM or more, where do memory-mapped I/O > devices get mapped (in the physical address space)? Most PCI devices > can't handle 64-bit addresses. Can PC chipsets physically remap some of > the RAM to above 4 gig? Or do you just lose that much RAM? If both RAM > and some I/O device are mapped to the same location, isn't there a conflict? AFAIK most (if not all) of that lands below 4GB in extant chipsets/BIOS's. Remapping above 4GB is possible but various things would probably barf. -- wli