From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932112AbaBROxi (ORCPT ); Tue, 18 Feb 2014 09:53:38 -0500 Received: from opensource.wolfsonmicro.com ([80.75.67.52]:35549 "EHLO opensource.wolfsonmicro.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756013AbaBROxh (ORCPT ); Tue, 18 Feb 2014 09:53:37 -0500 Date: Tue, 18 Feb 2014 14:53:34 +0000 From: Charles Keepax To: Dmitry Torokhov Cc: alsa-devel@alsa-project.org, lars@metafoo.de, eric.y.miao@gmail.com, patches@opensource.wolfsonmicro.com, lgirdwood@gmail.com, haojian.zhuang@gmail.com, linux-kernel@vger.kernel.org, peter.ujfalusi@ti.com, cw00.choi@samsung.com, broonie@kernel.org, myungjoo.ham@samsung.com, linux@arm.linux.org.uk, jarkko.nikula@bitmer.com Subject: Re: [alsa-devel] [PATCH 01/15] Input - arizona-haptics: Fix double lock of dapm_mutex Message-ID: <20140218145334.GA5438@opensource.wolfsonmicro.com> References: <1392655903-24537-1-git-send-email-ckeepax@opensource.wolfsonmicro.com> <1392655903-24537-2-git-send-email-ckeepax@opensource.wolfsonmicro.com> <20140217192025.GB19223@core.coreip.homeip.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140217192025.GB19223@core.coreip.homeip.net> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 17, 2014 at 11:20:26AM -0800, Dmitry Torokhov wrote: > HI Charles, > > On Mon, Feb 17, 2014 at 04:51:29PM +0000, Charles Keepax wrote: > > snd_soc_dapm_sync takes the dapm_mutex internally, but we currently take > > it externally as well. This patch fixes this. > > Hmm, from the first glance this needs to go into current release, > however it seems that it has been broken by > a73fb2df01866b772a48fab93401fe3edbe0b38d 2 years ago so nobody cares... > > Looking at the series I am not sure that this is right direction. You > actually do want unlocked versions of snd_soc_dapm_* functions so that > callers can take dapm mutex and then perform sequence of operations. The > currect callers that were taking the mutex should probbaly be changed so > that they do not drop it until they called unlocked version of > snd_soc_dapm_sync(). Having looked over this again I would prefer to go with the current fix. It means the fix can be sent to the stable trees and the haptics driver has no requirement for multiple pin updates to be done atomically, so there is not a huge amount to be gained from bundling things under an external lock. Thanks, Charles