target/linux/brcm2708/patches-4.19/950-0387-staging-bcm2835-audio-Drop-superfluous-mutex-lock-du.patch

   1 From 3c7663a9b1763f64250db4b975a3ce246ef32e0f Mon Sep 17 00:00:00 2001
   2 From: Takashi Iwai <tiwai@suse.de>
   3 Date: Tue, 4 Sep 2018 17:58:45 +0200
   4 Subject: [PATCH] staging: bcm2835-audio: Drop superfluous mutex lock
   5  during prepare
   6
   7 commit f0eb15d055380ff127e5f12c8fad2b36bdb3c006 upstream.
   8
   9 The chip->audio_mutex is used basically for protecting the opened
  10 stream assignment, and the prepare callback is irrelevant with it.
  11
  12 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  13 Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
  14 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  15 ---
  16  drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c | 8 ++------
  17  1 file changed, 2 insertions(+), 6 deletions(-)
  18
  19 --- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
  20 +++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
  21 @@ -218,8 +218,6 @@ static int snd_bcm2835_pcm_prepare(struc
  22         int channels;
  23         int err;
  24
  25 -       mutex_lock(&chip->audio_mutex);
  26 -
  27         /* notify the vchiq that it should enter spdif passthrough mode by
  28          * setting channels=0 (see
  29          * https://github.com/raspberrypi/linux/issues/528)
  30 @@ -233,7 +231,7 @@ static int snd_bcm2835_pcm_prepare(struc
  31                                        runtime->rate,
  32                                        snd_pcm_format_width(runtime->format));
  33         if (err < 0)
  34 -               goto out;
  35 +               return err;
  36
  37         memset(&alsa_stream->pcm_indirect, 0, sizeof(alsa_stream->pcm_indirect));
  38
  39 @@ -246,9 +244,7 @@ static int snd_bcm2835_pcm_prepare(struc
  40         alsa_stream->pos = 0;
  41         alsa_stream->draining = false;
  42
  43 - out:
  44 -       mutex_unlock(&chip->audio_mutex);
  45 -       return err;
  46 +       return 0;
  47  }
  48
  49  static void snd_bcm2835_pcm_transfer(struct snd_pcm_substream *substream,