target/linux/bcm27xx/patches-4.19/950-0388-staging-bcm2835-audio-Add-10ms-period-constraint.patch

   1 From daa78c198ece1ec901ee565c869ee1a60a95061d Mon Sep 17 00:00:00 2001
   2 From: Takashi Iwai <tiwai@suse.de>
   3 Date: Tue, 4 Sep 2018 17:58:46 +0200
   4 Subject: [PATCH] staging: bcm2835-audio: Add 10ms period constraint
   5
   6 commit 93c66acaf68b5247c3121a46a71ff6a70fc1d492 upstream.
   7
   8 It seems that the resolution of vc04 callback is in 10 msec; i.e. the
   9 minimal period size is also 10 msec.
  10
  11 This patch adds the corresponding hw constraint.
  12
  13 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  14 Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
  15 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  16 ---
  17  drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c | 5 +++++
  18  1 file changed, 5 insertions(+)
  19
  20 --- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
  21 +++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
  22 @@ -145,6 +145,11 @@ static int snd_bcm2835_playback_open_gen
  23                                    SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
  24                                    16);
  25
  26 +       /* position update is in 10ms order */
  27 +       snd_pcm_hw_constraint_minmax(runtime,
  28 +                                    SNDRV_PCM_HW_PARAM_PERIOD_TIME,
  29 +                                    10 * 1000, UINT_MAX);
  30 +
  31         chip->alsa_stream[idx] = alsa_stream;
  32
  33         chip->opened |= (1 << idx);