From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757256Ab1LNN6S (ORCPT ); Wed, 14 Dec 2011 08:58:18 -0500 Received: from multi.imgtec.com ([194.200.65.239]:23021 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757218Ab1LNN6S (ORCPT ); Wed, 14 Dec 2011 08:58:18 -0500 Message-ID: <4EE8AB76.6040202@imgtec.com> Date: Wed, 14 Dec 2011 13:58:14 +0000 From: James Hogan User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Lightning/1.0b2pre Thunderbird/3.0.10 MIME-Version: 1.0 To: Mark Brown CC: Liam Girdwood , Jaroslav Kysela , Takashi Iwai , , linux-kernel , Neil Subject: Re: bugs in "ASoC: core - Optimise and refactor pcm_new() to pass only rtd"? References: <4EE89A06.80101@imgtec.com> <20111214133448.GD25088@sirena.org.uk> In-Reply-To: <20111214133448.GD25088@sirena.org.uk> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 14 Dec 2011 13:58:14.0542 (UTC) FILETIME=[6C6E12E0:01CCBA68] X-SEF-Processed: 7_3_0_01158__2011_12_14_13_58_15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/14/2011 01:34 PM, Mark Brown wrote: > On Wed, Dec 14, 2011 at 12:43:50PM +0000, James Hogan wrote: > >> I've bisected a problem with an out of tree set of asoc drivers down to commit >> 552d1ef6b5a98d7b95959d5b139071e3c90cebf1 ("ASoC: core - Optimise and refactor >> pcm_new() to pass only rtd"). By the looks of it this change was intended not >> to change the workings of the code, however the dai parameter of pcm_new used >> to be passed codec_dai in soc_new_pcm() (initialised from rtd->codec_dai), but >> each driver now sets it's dai to rtd->cpu_dai instead. This seems to make the >> driver check the wrong dai's driver->capture.channels_min in the pcm_new >> callback, which makes it dereference >> pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream in the driver's >> preallocate_dma_buffer() function which can be NULL. Is this a bug (in every >> pcm asoc driver) that just happens not to have been noticed, or have I >> misunderstood it? > > Your drivers should never have beenn relying on this behaviour of the > core - see changes in the pxa and fsl drivers which remove similar > assumptions. The CPU driver should be checking for the substream if > it's looking to see if a particular substream is present, not peering > inside the DAI for a random parameter. Thanks Mark, we were basing our drivers on one of the other ones (I think the atmel one, which still seems to do it as of v3.2-rc4). Cheers James