From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 2 May 2002 17:29:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 2 May 2002 17:29:27 -0400 Received: from holomorphy.com ([66.224.33.161]:2520 "EHLO holomorphy") by vger.kernel.org with ESMTP id ; Thu, 2 May 2002 17:29:26 -0400 Date: Thu, 2 May 2002 14:28:10 -0700 From: William Lee Irwin III To: "Martin J. Bligh" Cc: Andrea Arcangeli , Daniel Phillips , Russell King , linux-kernel@vger.kernel.org Subject: Re: Bug: Discontigmem virt_to_page() [Alpha,ARM,Mips64?] Message-ID: <20020502212810.GN32767@holomorphy.com> Mail-Followup-To: William Lee Irwin III , "Martin J. Bligh" , Andrea Arcangeli , Daniel Phillips , Russell King , linux-kernel@vger.kernel.org In-Reply-To: <20020502180632.I11414@dualathlon.random> <3972036796.1020330599@[10.10.2.3]> <20020502184037.J11414@dualathlon.random> <20020502171655.GJ32767@holomorphy.com> <20020502204136.M11414@dualathlon.random> <20020502191903.GL32767@holomorphy.com> <148490000.1020378039@flay> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline User-Agent: Mutt/1.3.25i Organization: The Domain of Holomorphy Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 02, 2002 at 08:41:36PM +0200, Andrea Arcangeli wrote: >> I believe 64-bit PCI is pretty much taken to be a requirement; if it >> weren't the 4GB limit would once again apply and we'd be in much >> trouble, or we'd have to implement a different method of accommodating >> limited device addressing capabilities and would be in trouble again. On Thu, May 02, 2002 at 03:20:39PM -0700, Martin J. Bligh wrote: > IIRC, there are some funny games you can play with 32bit PCI DMA. > You're not necessarily restricted to the bottom 4Gb of phys addr space, > you're restricted to a 4Gb window, which you can shift by programming > a register on the card. Fixing that register to point to a window for the > node in question allows you to allocate from a node's pg_data_t and > assure DMAable RAM is returned. > M. Woops, I forgot about the BAR, thanks. Heck, IIRC you were even the one who told me about this trick. Thanks, Bill