ASoC: Intel: avs: Fix sound clipping in single capture scenario

To avoid sound clipping when there just one, single CAPTURE stream
ongoing, disable L1SEN before it is started. Any PLAYBACK stream or
additional CAPTURE allows L1SEN to be re-enabled.

Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://msgid.link/r/20240220115035.770402-3-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/avs/pcm.c

@@ -643,6 +643,79 @@ static int avs_dai_fe_prepare(struct snd_pcm_substream *substream, struct snd_so
 	return 0;
 }
 
+static void avs_hda_stream_start(struct hdac_bus *bus, struct hdac_ext_stream *host_stream)
+{
+	struct hdac_stream *first_running = NULL;
+	struct hdac_stream *pos;
+	struct avs_dev *adev = hdac_to_avs(bus);
+
+	list_for_each_entry(pos, &bus->stream_list, list) {
+		if (pos->running) {
+			if (first_running)
+				break; /* more than one running */
+			first_running = pos;
+		}
+	}
+
+	/*
+	 * If host_stream is a CAPTURE stream and will be the only one running,
+	 * disable L1SEN to avoid sound clipping.
+	 */
+	if (!first_running) {
+		if (hdac_stream(host_stream)->direction == SNDRV_PCM_STREAM_CAPTURE)
+			avs_hda_l1sen_enable(adev, false);
+		snd_hdac_stream_start(hdac_stream(host_stream));
+		return;
+	}
+
+	snd_hdac_stream_start(hdac_stream(host_stream));
+	/*
+	 * If host_stream is the first stream to break the rule above,
+	 * re-enable L1SEN.
+	 */
+	if (list_entry_is_head(pos, &bus->stream_list, list) &&
+	    first_running->direction == SNDRV_PCM_STREAM_CAPTURE)
+		avs_hda_l1sen_enable(adev, true);
+}
+
+static void avs_hda_stream_stop(struct hdac_bus *bus, struct hdac_ext_stream *host_stream)
+{
+	struct hdac_stream *first_running = NULL;
+	struct hdac_stream *pos;
+	struct avs_dev *adev = hdac_to_avs(bus);
+
+	list_for_each_entry(pos, &bus->stream_list, list) {
+		if (pos == hdac_stream(host_stream))
+			continue; /* ignore stream that is about to be stopped */
+		if (pos->running) {
+			if (first_running)
+				break; /* more than one running */
+			first_running = pos;
+		}
+	}
+
+	/*
+	 * If host_stream is a CAPTURE stream and is the only one running,
+	 * re-enable L1SEN.
+	 */
+	if (!first_running) {
+		snd_hdac_stream_stop(hdac_stream(host_stream));
+		if (hdac_stream(host_stream)->direction == SNDRV_PCM_STREAM_CAPTURE)
+			avs_hda_l1sen_enable(adev, true);
+		return;
+	}
+
+	/*
+	 * If by stopping host_stream there is only a single, CAPTURE stream running
+	 * left, disable L1SEN to avoid sound clipping.
+	 */
+	if (list_entry_is_head(pos, &bus->stream_list, list) &&
+	    first_running->direction == SNDRV_PCM_STREAM_CAPTURE)
+		avs_hda_l1sen_enable(adev, false);
+
+	snd_hdac_stream_stop(hdac_stream(host_stream));
+}
+
 static int avs_dai_fe_trigger(struct snd_pcm_substream *substream, int cmd, struct snd_soc_dai *dai)
 {
 	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
@@ -664,7 +737,7 @@ static int avs_dai_fe_trigger(struct snd_pcm_substream *substream, int cmd, stru
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		spin_lock_irqsave(&bus->reg_lock, flags);
-		snd_hdac_stream_start(hdac_stream(host_stream));
+		avs_hda_stream_start(bus, host_stream);
 		spin_unlock_irqrestore(&bus->reg_lock, flags);
 
 		/* Timeout on DRSM poll shall not stop the resume so ignore the result. */
@@ -694,7 +767,7 @@ static int avs_dai_fe_trigger(struct snd_pcm_substream *substream, int cmd, stru
 			dev_err(dai->dev, "pause FE path failed: %d\n", ret);
 
 		spin_lock_irqsave(&bus->reg_lock, flags);
-		snd_hdac_stream_stop(hdac_stream(host_stream));
+		avs_hda_stream_stop(bus, host_stream);
 		spin_unlock_irqrestore(&bus->reg_lock, flags);
 
 		ret = avs_path_reset(data->path);