[PATCH] ASoC: Intel: bxt: Refine the HW contraint of Ref capture.

[PATCH] ASoC: Intel: bxt: Refine the HW contraint of Ref capture.

[Harry Pan]

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.

Signed-off-by: Harry Pan <harry.pan@intel.com>
---
 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

Re: [PATCH] ASoC: Intel: bxt: Refine the HW contraint of Ref capture.

[Vinod Koul]

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@intel.com>
> ---
>  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