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

[Dylan Reid]

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>
---
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