From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from dehamd003.servertools24.de ([31.47.254.18]:35305 "EHLO dehamd003.servertools24.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753544AbbIASEm (ORCPT ); Tue, 1 Sep 2015 14:04:42 -0400 Message-ID: <55E5E625.5010403@ladisch.de> Date: Tue, 01 Sep 2015 19:53:41 +0200 From: Clemens Ladisch MIME-Version: 1.0 To: Shuah Khan CC: alsa-devel@alsa-project.org, linux-media@vger.kernel.org Subject: Re: [alsa-devel] Linux 4.2 ALSA snd-usb-audio inconsistent lock state warn in PCM nonatomic mode References: <55E4D9BE.2040308@osg.samsung.com> <55E564ED.4050609@ladisch.de> <55E5E31F.6040802@osg.samsung.com> In-Reply-To: <55E5E31F.6040802@osg.samsung.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Shuah Khan wrote:> On 09/01/2015 02:42 AM, Clemens Ladisch wrote: >> Shuah Khan wrote: >>> +++ b/sound/usb/stream.c >>> pcm->private_data = as; >>> pcm->private_free = snd_usb_audio_pcm_free; >>> pcm->info_flags = 0; >>> + pcm->nonatomic = true; >> >> Why do you think you need nonatomic mode in the USB audio driver? > > I have been working on adding Media Controller support for this chip > as chip specific feature in ALSA. This will allow sharing resources > such as the tuner across the drivers that control the device (DVB, > Video, snd-usb-audio). Media Controller framework uses a mutex to > protect access to resources, hence there is a need to hold this mutex > from SNDRV_PCM_TRIGGER_START and SNDRV_PCM_TRIGGER_STOP which could run > in IRQ context. Resources should be managed in the hw_params/hw_free callbacks. Regards, Clemens