Re: [alsa-devel] [PATCH v2] ASoC: Intel: kbl_rt5663_rt5514_max98927: Add dmic format constraint

[Pierre-Louis Bossart]

On 9/23/19 11:29 AM, Yu-Hsuan Hsu wrote:
> On KBL platform, the microphone is attached to external codec(rt5514)
> instead of PCH. However, TDM slot between PCH and codec is 16 bits only.
> In order to avoid setting wrong format, we should add a constraint to
> force to use 16 bits format forever.
>
> Signed-off-by: Yu-Hsuan Hsu <yuhsuan@xxxxxxxxxxxx>
> ---
> I have updated the commit message. Please see whether it is clear
> enough. Thanks.

Sorry, I missed this patch. Looks ok, though the 'right' approach would 
be to have topology and/or copiers deal with format changes.

Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>


>   sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c b/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c
> index 74dda8784f1a01..67b276a65a8d2d 100644
> --- a/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c
> +++ b/sound/soc/intel/boards/kbl_rt5663_rt5514_max98927.c
> @@ -400,6 +400,9 @@ static int kabylake_dmic_startup(struct snd_pcm_substream *substream)
>   	snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
>   			dmic_constraints);
>   
> +	runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
> +	snd_pcm_hw_constraint_msbits(runtime, 0, 16, 16);
> +
>   	return snd_pcm_hw_constraint_list(substream->runtime, 0,
>   			SNDRV_PCM_HW_PARAM_RATE, &constraints_rates);
>   }