On Wed, Dec 06, 2017 at 03:21:27AM +0800, Harry Pan wrote:
> The patch restricts the HW contraint of the refcap of WoV stream
> in single channel (mono) and 16k Hz based on platform implementation.
>
> Such that, the userspace program can rely on correct HW parameters
> through the ALSA library call to manipulate the device.
I think this has been discussed earlier in the context of kbl machine and we
dont want kernel to have such restrictions. User space can request and open
a mono stream..
>
> Signed-off-by: Harry Pan <harry.pan@xxxxxxxxx>
> ---
> sound/soc/intel/boards/bxt_da7219_max98357a.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/sound/soc/intel/boards/bxt_da7219_max98357a.c b/sound/soc/intel/boards/bxt_da7219_max98357a.c
> index ce35ec7884d1..382f71228807 100644
> --- a/sound/soc/intel/boards/bxt_da7219_max98357a.c
> +++ b/sound/soc/intel/boards/bxt_da7219_max98357a.c
> @@ -338,8 +338,23 @@ static const struct snd_pcm_hw_constraint_list constraints_16000 = {
> .list = rates_16000,
> };
>
> +static const unsigned int ch_mono[] = {
> + 1,
> +};
> +
> +static const struct snd_pcm_hw_constraint_list constraints_refcap = {
> + .count = ARRAY_SIZE(ch_mono),
> + .list = ch_mono,
> +};
> +
> static int broxton_refcap_startup(struct snd_pcm_substream *substream)
> {
> + substream->runtime->hw.channels_max = 1;
> +
> + snd_pcm_hw_constraint_list(substream->runtime, 0,
> + SNDRV_PCM_HW_PARAM_CHANNELS,
> + &constraints_refcap);
> +
> return snd_pcm_hw_constraint_list(substream->runtime, 0,
> SNDRV_PCM_HW_PARAM_RATE,
> &constraints_16000);
> --
> 2.13.5
>
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--
~Vinod
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