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From: Takashi Iwai <tiwai@suse.de>
To: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Eric Anholt <eric@anholt.net>,
	linux-rpi-kernel@lists.infradead.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 16/29] staging: bcm2835-audio: Drop superfluous mutex lock during prepare
Date: Sat, 08 Sep 2018 18:12:58 +0200
Message-ID: <s5hftyk55o5.wl-tiwai@suse.de> (raw)
In-Reply-To: <1706035173.39231.1536414041437@email.1und1.de>

On Sat, 08 Sep 2018 15:40:41 +0200,
Stefan Wahren wrote:
> 
> Hi,
> 
> > Takashi Iwai <tiwai@suse.de> hat am 4. September 2018 um 17:58 geschrieben:
> > 
> > 
> > The chip->audio_mutex is used basically for protecting the opened
> > stream assignment, and the prepare callback is irrelevant with it.
> > 
> > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > ---
> >  drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c | 8 ++------
> >  1 file changed, 2 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
> > index 1f9c940f1cc3..9659c25b9f9d 100644
> > --- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
> > +++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
> > @@ -218,8 +218,6 @@ static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream)
> >  	int channels;
> >  	int err;
> >  
> > -	mutex_lock(&chip->audio_mutex);
> > -
> >  	/* notify the vchiq that it should enter spdif passthrough mode by
> >  	 * setting channels=0 (see
> >  	 * https://github.com/raspberrypi/linux/issues/528)
> > @@ -233,7 +231,7 @@ static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream)
> >  				       runtime->rate,
> >  				       snd_pcm_format_width(runtime->format));
> >  	if (err < 0)
> > -		goto out;
> > +		return err;
> >  
> >  	memset(&alsa_stream->pcm_indirect, 0, sizeof(alsa_stream->pcm_indirect));
> >  
> > @@ -246,9 +244,7 @@ static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream)
> >  	alsa_stream->pos = 0;
> >  	alsa_stream->draining = false;
> >  
> > - out:
> > -	mutex_unlock(&chip->audio_mutex);
> > -	return err;
> > +	return 0;
> 
> looks like your are removing code which has been added in patch #14 ?

No, the patch #14 corrects the missing error path.  Without patch 14,
the error from prepare is ignored.  And this patch gets rid of the
superfluous mutex lock.


thanks,

Takashi

  reply index

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-04 15:58 [PATCH 00/29] staging: bcm2835-audio: Cleanups and fixes Takashi Iwai
2018-09-04 15:58 ` [PATCH 01/29] staging: bcm2835-audio: Clean up mutex locks Takashi Iwai
2018-09-04 15:58 ` [PATCH 02/29] staging: bcm2835-audio: Remove redundant spdif stream ctls Takashi Iwai
2018-09-04 15:58 ` [PATCH 03/29] staging: bcm2835-audio: Clean up include files in bcm2835-ctl.c Takashi Iwai
2018-09-08 13:25   ` Stefan Wahren
2018-09-08 16:21     ` Takashi Iwai
2018-09-04 15:58 ` [PATCH 04/29] staging: bcm2835-audio: Remove redundant substream mask checks Takashi Iwai
2018-09-04 15:58 ` [PATCH 05/29] staging: bcm2835-audio: Fix mute controls, volume handling cleanup Takashi Iwai
2018-09-04 15:58 ` [PATCH 06/29] staging: bcm2835-audio: Remove redundant function calls Takashi Iwai
2018-09-04 15:58 ` [PATCH 07/29] staging: bcm2835-audio: Remove superfluous open flag Takashi Iwai
2018-09-04 15:58 ` [PATCH 08/29] staging: bcm2835-audio: Drop useless running flag and check Takashi Iwai
2018-09-04 15:58 ` [PATCH 09/29] staging: bcm2835-audio: Fix incorrect draining handling Takashi Iwai
2018-09-04 15:58 ` [PATCH 10/29] staging: bcm2835-audio: Kill unused spinlock Takashi Iwai
2018-09-04 15:58 ` [PATCH 11/29] staging: bcm2835-audio: Use PCM runtime values instead Takashi Iwai
2018-09-04 15:58 ` [PATCH 12/29] staging: bcm2835-audio: Drop unnecessary pcm indirect setup Takashi Iwai
2018-09-04 15:58 ` [PATCH 13/29] staging: bcm2835-audio: Drop useless NULL check Takashi Iwai
2018-09-04 15:58 ` [PATCH 14/29] staging: bcm2835-audio: Propagate parameter setup error Takashi Iwai
2018-09-04 15:58 ` [PATCH 15/29] staging: bcm2835-audio: Drop debug messages in bcm2835-pcm.c Takashi Iwai
2018-09-04 15:58 ` [PATCH 16/29] staging: bcm2835-audio: Drop superfluous mutex lock during prepare Takashi Iwai
2018-09-08 13:40   ` Stefan Wahren
2018-09-08 16:12     ` Takashi Iwai [this message]
2018-09-04 15:58 ` [PATCH 17/29] staging: bcm2835-audio: Add 10ms period constraint Takashi Iwai
2018-09-19  9:42   ` Stefan Wahren
2018-09-19  9:52     ` Takashi Iwai
2018-09-19 12:41       ` Stefan Wahren
2018-09-19 12:47         ` Mike Brady
2018-09-19 18:39         ` Takashi Iwai
2018-10-09 13:18           ` [PATCH 17/29] staging: bcm2835-audio: Add 10ms period constraint [Resend in plain text...] Mike Brady
2018-10-09 13:44             ` Takashi Iwai
2018-10-09 15:28               ` Mike Brady
2018-10-09 15:32                 ` Takashi Iwai
2018-10-11 12:53                 ` Mike Brady
2018-10-11 14:07                   ` Stefan Wahren
2018-10-13 15:00                   ` Mike Brady
2018-10-13 15:45                     ` Takashi Iwai
2018-09-04 15:58 ` [PATCH 18/29] staging: bcm2835-audio: Make single vchi handle Takashi Iwai
2018-09-04 15:58 ` [PATCH 19/29] staging: bcm2835-audio: Code refactoring of vchiq accessor codes Takashi Iwai
2018-09-04 15:58 ` [PATCH 20/29] staging: bcm2835-audio: Operate non-atomic PCM ops Takashi Iwai
2018-09-04 15:58 ` [PATCH 21/29] staging: bcm2835-audio: Use card->private_data Takashi Iwai
2018-09-04 15:58 ` [PATCH 22/29] staging: bcm2835-audio: Use standard error print helpers Takashi Iwai
2018-09-04 15:58 ` [PATCH 23/29] staging: bcm2835-audio: Remove unnecessary header file includes Takashi Iwai
2018-09-04 15:58 ` [PATCH 24/29] staging: bcm2835-audio: Move module parameter description Takashi Iwai
2018-09-04 15:58 ` [PATCH 25/29] staging: bcm2835-audio: Use coherent device buffers Takashi Iwai
2018-09-04 15:58 ` [PATCH 26/29] staging: bcm2835-audio: Set SNDRV_PCM_INFO_SYNC_APPLPTR Takashi Iwai
2018-09-04 15:58 ` [PATCH 27/29] staging: bcm2835-audio: Simplify PCM creation helpers Takashi Iwai
2018-09-04 15:58 ` [PATCH 28/29] staging: bcm2835-audio: Simplify kctl " Takashi Iwai
2018-09-04 15:58 ` [PATCH 29/29] staging: bcm2835-audio: Simplify card object management Takashi Iwai
2018-09-08 13:18 ` [PATCH 00/29] staging: bcm2835-audio: Cleanups and fixes Stefan Wahren
2018-09-08 16:21   ` Takashi Iwai
2018-09-08 17:00     ` Stefan Wahren
2018-09-08 17:16       ` Takashi Iwai
2018-09-10  9:12     ` Greg Kroah-Hartman
2018-09-10  9:16       ` Takashi Iwai

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