From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761084AbYENP0T (ORCPT ); Wed, 14 May 2008 11:26:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751625AbYENP0H (ORCPT ); Wed, 14 May 2008 11:26:07 -0400 Received: from g1t0028.austin.hp.com ([15.216.28.35]:33074 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbYENP0F (ORCPT ); Wed, 14 May 2008 11:26:05 -0400 From: Bjorn Helgaas To: Rene Herman Subject: Re: 2.6.26-rc1 regression: ISA DMA broken (bisected) Date: Wed, 14 May 2008 09:26:04 -0600 User-Agent: KMail/1.9.6 (enterprise 0.20070907.709405) Cc: Alan Cox , Takashi Iwai , Glauber Costa , Ingo Molnar , Thomas Gleixner , Pete Clements , Linux Kernel , ALSA devel References: <4823AAF2.7070102@keyaccess.nl> <200805131718.40138.bjorn.helgaas@hp.com> <482ADF34.2010004@keyaccess.nl> In-Reply-To: <482ADF34.2010004@keyaccess.nl> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200805140926.05103.bjorn.helgaas@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 14 May 2008 06:46:44 am Rene Herman wrote: > On 14-05-08 01:18, Bjorn Helgaas wrote: > > > On Tuesday 13 May 2008 11:33:25 am Rene Herman wrote: > > >> No, isa_device is its own thing, on its own isa_bus (*). It has a struct > >> device * readily available though... > >> > >> (*) drivers/base/isa.c, and explanatory changelog at: > >> > >> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a5117ba7da37deb09df5eb802dace229b3fb1e9f > > > > Thanks for the nice changelog. > > > > isa_register_driver() currently doesn't set a DMA mask. Should it? > > If it's going to be useful, definitely. The attached does not just set > > dev->dma_mask = &dev->coherent_dma_mask > > as in the fallback_dev when dma_alloc_coherent() is passed a NULL device > only due to the mask juggling in snd_dma_hack_alloc_coherent() (which > wouldn't break, but...) but introduces its own copy in struct isa_dev > same as struct pnp_dev. As far as I'm aware, there's no actual reason > for keeping it other than that and if the hack could go I'd rather lose > the private mask copy again also. > > (the device model still uses a plain u64 by the way but I guess the > clean type would be a dma64_addr_t) > > Inlining is whitespace-failing here. Patch itself is trivial... > > > I only see about 35 dma_alloc_coherent() calls that pass NULL. I > > guess even those would be a fair amount of work to change, and I > > suppose there would be more that I missed. > > At least the ALSA one isn't passing a literal NULL it seems. But yes, > current NULL-hack reinstatement (it's been merged by Linus already) is > definitely the correct fix for now. > > Would like a comment on the snd_dma_hack_alloc_coherent thing first (no > signoff...) but other than that I'll submit this in preparation for it > being useful, I guess? Yes, I like this patch.