From: Clemens Ladisch <clemens@ladisch.de>
To: Shuah Khan <shuahkh@osg.samsung.com>
Cc: alsa-devel@alsa-project.org, linux-media@vger.kernel.org
Subject: Re: Linux 4.2 ALSA snd-usb-audio inconsistent lock state warn in PCM nonatomic mode
Date: Tue, 01 Sep 2015 19:53:41 +0200 [thread overview]
Message-ID: <55E5E625.5010403@ladisch.de> (raw)
In-Reply-To: <55E5E31F.6040802@osg.samsung.com>
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
WARNING: multiple messages have this Message-ID (diff)
From: Clemens Ladisch <clemens@ladisch.de>
To: Shuah Khan <shuahkh@osg.samsung.com>
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
Date: Tue, 01 Sep 2015 19:53:41 +0200 [thread overview]
Message-ID: <55E5E625.5010403@ladisch.de> (raw)
In-Reply-To: <55E5E31F.6040802@osg.samsung.com>
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
next prev parent reply other threads:[~2015-09-01 17:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-31 22:48 Linux 4.2 ALSA snd-usb-audio inconsistent lock state warn in PCM nonatomic mode Shuah Khan
2015-08-31 22:48 ` Shuah Khan
2015-09-01 4:47 ` Takashi Iwai
2015-09-01 4:47 ` Takashi Iwai
2015-09-01 8:42 ` Clemens Ladisch
2015-09-01 17:40 ` [alsa-devel] " Shuah Khan
2015-09-01 17:53 ` Clemens Ladisch [this message]
2015-09-01 17:53 ` Clemens Ladisch
2015-09-02 14:54 ` Shuah Khan
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