[alsa-devel] [PATCH v2] ALSA: hda/ca0132 - Update latency based on DSP state.

[Takashi Iwai]

At Thu,  4 Apr 2013 13:55:09 -0700,
Dylan Reid wrote:
> 
> The DSP in the CA0132 codec adds a variable latency to audio depending
> on what processing is being done.  Add a new patch op to return that
> latency for capture and playback streams.  The latency is determined
> by which blocks are enabled and knowing how much latency is added by
> each block.
> 
> Signed-off-by: Dylan Reid <dgreid at chromium.org>

Thanks, applied.


Takashi

> ---
> Changes since v1:
> Rebase on tiwai's patch to add a pcm_op, this is dependent on that.
> Get ms to frames conversion right.
> Test loopback and compare measured vs reported latency.
> 
>  sound/pci/hda/patch_ca0132.c | 55 ++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 53 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/pci/hda/patch_ca0132.c b/sound/pci/hda/patch_ca0132.c
> index 12eb21a..841842c 100644
> --- a/sound/pci/hda/patch_ca0132.c
> +++ b/sound/pci/hda/patch_ca0132.c
> @@ -131,6 +131,13 @@ enum {
>  /* Effects values size*/
>  #define EFFECT_VALS_MAX_COUNT 12
>  
> +/* Latency introduced by DSP blocks in milliseconds. */
> +#define DSP_CAPTURE_INIT_LATENCY        0
> +#define DSP_CRYSTAL_VOICE_LATENCY       124
> +#define DSP_PLAYBACK_INIT_LATENCY       13
> +#define DSP_PLAY_ENHANCEMENT_LATENCY    30
> +#define DSP_SPEAKER_OUT_LATENCY         7
> +
>  struct ct_effect {
>  	char name[44];
>  	hda_nid_t nid;
> @@ -2743,6 +2750,31 @@ static int ca0132_playback_pcm_cleanup(struct hda_pcm_stream *hinfo,
>  	return 0;
>  }
>  
> +static unsigned int ca0132_playback_pcm_delay(struct hda_pcm_stream *info,
> +			struct hda_codec *codec,
> +			struct snd_pcm_substream *substream)
> +{
> +	struct ca0132_spec *spec = codec->spec;
> +	unsigned int latency = DSP_PLAYBACK_INIT_LATENCY;
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +
> +	if (spec->dsp_state != DSP_DOWNLOADED)
> +		return 0;
> +
> +	/* Add latency if playback enhancement and either effect is enabled. */
> +	if (spec->effects_switch[PLAY_ENHANCEMENT - EFFECT_START_NID]) {
> +		if ((spec->effects_switch[SURROUND - EFFECT_START_NID]) ||
> +		    (spec->effects_switch[DIALOG_PLUS - EFFECT_START_NID]))
> +			latency += DSP_PLAY_ENHANCEMENT_LATENCY;
> +	}
> +
> +	/* Applying Speaker EQ adds latency as well. */
> +	if (spec->cur_out_type == SPEAKER_OUT)
> +		latency += DSP_SPEAKER_OUT_LATENCY;
> +
> +	return (latency * runtime->rate) / 1000;
> +}
> +
>  /*
>   * Digital out
>   */
> @@ -2811,6 +2843,23 @@ static int ca0132_capture_pcm_cleanup(struct hda_pcm_stream *hinfo,
>  	return 0;
>  }
>  
> +static unsigned int ca0132_capture_pcm_delay(struct hda_pcm_stream *info,
> +			struct hda_codec *codec,
> +			struct snd_pcm_substream *substream)
> +{
> +	struct ca0132_spec *spec = codec->spec;
> +	unsigned int latency = DSP_CAPTURE_INIT_LATENCY;
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +
> +	if (spec->dsp_state != DSP_DOWNLOADED)
> +		return 0;
> +
> +	if (spec->effects_switch[CRYSTAL_VOICE - EFFECT_START_NID])
> +		latency += DSP_CRYSTAL_VOICE_LATENCY;
> +
> +	return (latency * runtime->rate) / 1000;
> +}
> +
>  /*
>   * Controls stuffs.
>   */
> @@ -4002,7 +4051,8 @@ static struct hda_pcm_stream ca0132_pcm_analog_playback = {
>  	.channels_max = 6,
>  	.ops = {
>  		.prepare = ca0132_playback_pcm_prepare,
> -		.cleanup = ca0132_playback_pcm_cleanup
> +		.cleanup = ca0132_playback_pcm_cleanup,
> +		.get_delay = ca0132_playback_pcm_delay,
>  	},
>  };
>  
> @@ -4012,7 +4062,8 @@ static struct hda_pcm_stream ca0132_pcm_analog_capture = {
>  	.channels_max = 2,
>  	.ops = {
>  		.prepare = ca0132_capture_pcm_prepare,
> -		.cleanup = ca0132_capture_pcm_cleanup
> +		.cleanup = ca0132_capture_pcm_cleanup,
> +		.get_delay = ca0132_capture_pcm_delay,
>  	},
>  };
>  
> -- 
> 1.8.1.5
>