[alsa-devel] [PATCH 3/4] ALSA: CA0132: Add latency monitoring

[Takashi Iwai]

At Fri, 8 Feb 2013 18:31:44 -0800,
Ian Minett wrote:
> 
> From: Ian Minett <ian_minett at creativelabs.com>
> 
> Add latency monitoring for playback, capture and DSP effects.

Please give a bit more descriptions.
Looking at the patch, it doesn't implement only the latency monitoring
but actually reflecting to the runtime->delay.

Also..


> Signed-off-by: Ian Minett <ian_minett at creativelabs.com>
> 
> diff --git a/sound/pci/hda/patch_ca0132.c b/sound/pci/hda/patch_ca0132.c
> index b52f00c..c797f65 100644
> --- a/sound/pci/hda/patch_ca0132.c
> +++ b/sound/pci/hda/patch_ca0132.c
> @@ -133,6 +133,12 @@ enum {
>  /* Effects values size*/
>  #define EFFECT_VALS_MAX_COUNT 12
>  
> +#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;
> @@ -2761,8 +2767,27 @@ static void ca0132_cleanup_stream(struct hda_codec *codec, hda_nid_t nid)
>  }
>  
>  /*
> - * PCM callbacks
> + * PCM playbacks
>   */
> +static unsigned int ca0132_get_playback_latency(struct hda_codec *codec)
> +{
> +	struct ca0132_spec *spec = codec->spec;
> +	unsigned int latency = DSP_PLAYBACK_INIT_LATENCY;
> +
> +	if (!dspload_is_loaded(codec))
> +		return 0;
> +
> +	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;
> +	}
> +
> +	if (spec->cur_out_type == SPEAKER_OUT)
> +		latency += DSP_SPEAKER_OUT_LATENCY;
> +	return latency;
> +}
> +
>  static int ca0132_playback_pcm_prepare(struct hda_pcm_stream *hinfo,
>  			struct hda_codec *codec,
>  			unsigned int stream_tag,
> @@ -2770,6 +2795,16 @@ static int ca0132_playback_pcm_prepare(struct hda_pcm_stream *hinfo,
>  			struct snd_pcm_substream *substream)
>  {
>  	struct ca0132_spec *spec = codec->spec;
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	unsigned int latency = ca0132_get_playback_latency(codec);
> +
> +	if (spec->dsp_state == DSP_DOWNLOADING) {
> +		spec->dsp_stream_id = stream_tag;
> +		return 0;
> +	}
> +
> +	runtime->delay = bytes_to_frames(runtime, (latency * runtime->rate *
> +					runtime->byte_align) / 1000);
>  
>  	ca0132_setup_stream(codec, spec->dacs[0], stream_tag, 0, format);
>  
> @@ -2834,8 +2869,22 @@ static int ca0132_dig_playback_pcm_close(struct hda_pcm_stream *hinfo,
>  }
>  
>  /*
> - * Analog capture
> + * PCM capture
>   */
> +
> +static unsigned int ca0132_get_capture_latency(struct hda_codec *codec)
> +{
> +	struct ca0132_spec *spec = codec->spec;
> +	unsigned int latency = DSP_CAPTURE_INIT_LATENCY;
> +
> +	if (!dspload_is_loaded(codec))
> +		return 0;
> +
> +	if (spec->effects_switch[CRYSTAL_VOICE - EFFECT_START_NID])
> +		latency += DSP_CRYSTAL_VOICE_LATENCY;
> +	return latency;
> +}
> +
>  static int ca0132_capture_pcm_prepare(struct hda_pcm_stream *hinfo,
>  					struct hda_codec *codec,
>  					unsigned int stream_tag,
> @@ -2843,9 +2892,16 @@ static int ca0132_capture_pcm_prepare(struct hda_pcm_stream *hinfo,
>  					struct snd_pcm_substream *substream)
>  {
>  	struct ca0132_spec *spec = codec->spec;
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +	unsigned int latency = ca0132_get_capture_latency(codec);
>  
> -	ca0132_setup_stream(codec, spec->adcs[substream->number],
> -			    stream_tag, 0, format);
> +	if (spec->dsp_state == DSP_DOWNLOADING)
> +		return 0;
> +
> +	runtime->delay = bytes_to_frames(runtime, (latency * runtime->rate *
> +					runtime->byte_align) / 1000);
> +
> +	ca0132_setup_stream(codec, hinfo->nid, stream_tag, 0, format);
>  
>  	return 0;
>  }
> @@ -3429,6 +3485,33 @@ static int ca0132_voicefx_set(struct hda_codec *codec, int enable)
>  	return 1;
>  }
>  
> +static void ca0132_update_latency(struct hda_codec *codec,
> +				  unsigned int direction)
> +{
> +	struct ca0132_spec *spec = codec->spec;
> +	unsigned int latency;
> +	struct snd_pcm_substream *substr;
> +	struct snd_pcm_runtime *runtime;
> +
> +	if (spec->dsp_state == DSP_DOWNLOADING)
> +		return;
> +
> +	latency = (direction == SNDRV_PCM_STREAM_PLAYBACK)
> +			? ca0132_get_playback_latency(codec)
> +			: ca0132_get_capture_latency(codec);
> +
> +	substr = codec->pcm_info->pcm->streams[direction].substream;
> +	while (substr) {
> +		runtime = substr->runtime;
> +		/* update latency only when frame_bits is set */
> +		if (runtime && runtime->frame_bits)
> +			runtime->delay = bytes_to_frames(runtime,
> +					(latency * runtime->rate *
> +					runtime->byte_align) / 1000);
> +		substr = substr->next;
> +	}

I guess this isn't needed.  Usually the pointer callback is performed
always before the inquiry of runtime->delay.


Takashi


> +}
> +
>  /*
>   * Set the effects parameters
>   */
> @@ -3468,6 +3551,9 @@ static int ca0132_effects_set(struct hda_codec *codec, hda_nid_t nid, long val)
>  	err = dspio_set_uint_param(codec, ca0132_effects[idx].mid,
>  				   ca0132_effects[idx].reqs[0], on);
>  
> +	ca0132_update_latency(codec, SNDRV_PCM_STREAM_PLAYBACK);
> +	ca0132_update_latency(codec, SNDRV_PCM_STREAM_CAPTURE);
> +
>  	if (err < 0)
>  		return 0; /* no changed */
>  
> -- 
> 1.7.4.1
>