Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262883AbTFGJbN (ORCPT ); Sat, 7 Jun 2003 05:31:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262884AbTFGJbN (ORCPT ); Sat, 7 Jun 2003 05:31:13 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:7684 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S262883AbTFGJbH (ORCPT ); Sat, 7 Jun 2003 05:31:07 -0400 Date: Sat, 7 Jun 2003 10:44:34 +0100 From: Russell King To: davidm@hpl.hp.com Cc: "David S. Miller" , manfred@colorfullife.com, axboe@suse.de, linux-kernel@vger.kernel.org Subject: Re: problem with blk_queue_bounce_limit() Message-ID: <20030607104434.B22665@flint.arm.linux.org.uk> Mail-Followup-To: davidm@hpl.hp.com, "David S. Miller" , manfred@colorfullife.com, axboe@suse.de, linux-kernel@vger.kernel.org References: <16096.16492.286361.509747@napali.hpl.hp.com> <20030606.003230.15263591.davem@redhat.com> <200306062013.h56KDcLe026713@napali.hpl.hp.com> <20030606.234401.104035537.davem@redhat.com> <16097.37454.827982.278024@napali.hpl.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <16097.37454.827982.278024@napali.hpl.hp.com>; from davidm@napali.hpl.hp.com on Sat, Jun 07, 2003 at 12:20:46AM -0700 X-Message-Flag: Your copy of Microsoft Outlook is vulnerable to viruses. See www.mutt.org for more details. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 28 On Sat, Jun 07, 2003 at 12:20:46AM -0700, David Mosberger wrote: > ./include/asm-arm/pci.h:#define PCI_DMA_BUS_IS_PHYS (0) I suspect we probably set this incorrectly; we have some platforms where there is merely an offset between the phys address and the bus address. For these, I think we want to set this to 1. Other platforms require the dma functions to allocate a new buffer and copy the data to work around buggy "wont fix" errata (eg, new buffer below 1MB) and for these I think we want to leave this at 0. It is rather unfortunate that this got called "PCI_xxx" since it has been used in a non pci-bus manner in (eg) the scsi layer. Also note that I have platforms where the dma_mask is a real mask not "a set of zeros followed by a set of ones from MSB to LSB." I can see this breaking the block layer if PCI_DMA_BUS_IS_PHYS is defined to one. 8/ -- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html - 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/