Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764632AbXHFWtO (ORCPT ); Mon, 6 Aug 2007 18:49:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765607AbXHFWsq (ORCPT ); Mon, 6 Aug 2007 18:48:46 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:41792 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765851AbXHFWsp (ORCPT ); Mon, 6 Aug 2007 18:48:45 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Message-ID: <46B7A537.9020807@s5r6.in-berlin.de> Date: Tue, 07 Aug 2007 00:48:23 +0200 From: Stefan Richter User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.5) Gecko/20070804 SeaMonkey/1.1.3 MIME-Version: 1.0 To: Robert Hancock CC: Benjamin Herrenschmidt , Olaf Hering , linuxppc-dev@ozlabs.org, stable@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.6.22.y] ieee1394: revert "sbp2: enforce 32bit DMA mapping" References: <46B4B3DC.7020609@shaw.ca> <46B4B7C6.1040107@s5r6.in-berlin.de> <1186272926.938.8.camel@localhost.localdomain> <46B5824B.1000103@s5r6.in-berlin.de> <1186351473.938.21.camel@localhost.localdomain> <20070806135124.GA2900@suse.de> <1186436848.938.75.camel@localhost.localdomain> <46B79F25.50205@s5r6.in-berlin.de> <46B79FD7.9020801@shaw.ca> In-Reply-To: <46B79FD7.9020801@shaw.ca> X-Enigmail-Version: 0.95.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 31 Robert Hancock wrote: > Stefan Richter wrote: >> So that's the story why that dma_set_mask went into sbp2: Sbp2 wants >> mappings in a _subset_ of the OHCI-1394 controllers DMA range. >> >> Anyway. For now I will simply go with what 2.6.23-rc has and what >> 2.6.21 had: No dma_set_mask anywhere in the 1394 subsystem. We can >> revisit this whenever an actual need arises. > > Not sure this is a very good idea. This seems rather likely to fail on > x86_64 machines with >4GB of RAM for example.. I'll deal with it when a bug report comes in. 1.) The ieee1394 subsystem is known to work on x86_64 with more than 4 GB RAM, so I gather that architecture code already sets a proper DMA mask for all those 32bit PCI OHCI-1394 implementations out there. 2.) I haven't heard of an OHCI-1394 chip whose overall DMA range was bigger than the Physical Range. There are only two chips, from ALi and from Fujitsu, whose Physical Range is curiously bigger than the actual DMA range. -- Stefan Richter -=====-=-=== =--- --=== http://arcgraph.de/sr/ - 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/