Use constraint to make sure the period size could always be multiple of 1ms to align with the fundamental design/limitation of firmware. Signed-off-by: Brent Lu <brent.lu@xxxxxxxxx> --- sound/soc/intel/atom/sst-mfld-platform-pcm.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c index 49b9f18..5f89956 100644 --- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c +++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c @@ -333,6 +333,17 @@ static int sst_media_open(struct snd_pcm_substream *substream, if (ret_val < 0) return ret_val; + /* + * Make sure the period to be multiple of 1ms to align the + * design of firmware. Apply same rule to buffer size to make + * sure alsa could always find a value for period size + * regardless the buffer size given by user space. + */ + snd_pcm_hw_constraint_step(substream->runtime, 0, + SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 48); + snd_pcm_hw_constraint_step(substream->runtime, 0, + SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 48); + /* Make sure, that the period size is always even */ snd_pcm_hw_constraint_step(substream->runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS, 2); -- 2.7.4
