audio: implement mute on hdmi multichannel

On direct output streams the audio HAL must implement
the volume function. In the case of HDMI the only function
required is to mute audio when volume is 0 as volume
is defined as fixed on digital output streams.

Bug 8541062

Change-Id: I4b4e28a910e7b321b3a68567e9ad03fede065ca8

1 files changed, 18 insertions, 1 deletions

diff --git a/audio/audio_hw.c b/audio/audio_hw.c
index c5f1867..6f14e1e 100644
--- a/audio/audio_hw.c
+++ b/audio/audio_hw.c
@@ -691,6 +691,7 @@ struct tuna_stream_out {
     /* FIXME: workaround for HDMI multi channel channel swap on first playback after opening
      * the output stream: force reopening the pcm driver after writing a few periods. */
     int restart_periods_cnt;
+    bool muted;
 
     struct tuna_audio_device *dev;
 };
@@ -1918,6 +1919,16 @@ static int out_set_volume(struct audio_stream_out *stream, float left,
     return -ENOSYS;
 }
 
+static int out_set_volume_hdmi(struct audio_stream_out *stream, float left,
+                          float right)
+{
+    struct tuna_stream_out *out = (struct tuna_stream_out *)stream;
+
+    /* only take left channel into account: the API is for stereo anyway */
+    out->muted = (left == 0.0f);
+    return 0;
+}
+
 static ssize_t out_write_low_latency(struct audio_stream_out *stream, const void* buffer,
                          size_t bytes)
 {
@@ -2127,6 +2138,9 @@ static ssize_t out_write_hdmi(struct audio_stream_out *stream, const void* buffe
     }
     pthread_mutex_unlock(&adev->lock);
 
+    if (out->muted)
+        memset((void *)buffer, 0, bytes);
+
     ret = pcm_write(out->pcm[PCM_HDMI],
                    buffer,
                    pcm_frames_to_bytes(out->pcm[PCM_HDMI], in_frames));
@@ -3248,6 +3262,7 @@ static int adev_open_output_stream(struct audio_hw_device *dev,
         out->stream.common.get_sample_rate = out_get_sample_rate_hdmi;
         out->stream.get_latency = out_get_latency_hdmi;
         out->stream.write = out_write_hdmi;
+        out->stream.set_volume = out_set_volume_hdmi;
         out->config[PCM_HDMI] = pcm_config_hdmi_multi;
         out->config[PCM_HDMI].rate = config->sample_rate;
         out->config[PCM_HDMI].channels = popcount(config->channel_mask);
@@ -3265,6 +3280,7 @@ static int adev_open_output_stream(struct audio_hw_device *dev,
         out->stream.common.get_sample_rate = out_get_sample_rate;
         out->stream.get_latency = out_get_latency_deep_buffer;
         out->stream.write = out_write_deep_buffer;
+        out->stream.set_volume = out_set_volume;
     } else {
         ALOGV("adev_open_output_stream() normal buffer");
         if (ladev->outputs[OUTPUT_LOW_LATENCY] != NULL) {
@@ -3276,6 +3292,7 @@ static int adev_open_output_stream(struct audio_hw_device *dev,
         out->stream.common.get_sample_rate = out_get_sample_rate;
         out->stream.get_latency = out_get_latency_low_latency;
         out->stream.write = out_write_low_latency;
+        out->stream.set_volume = out_set_volume;
     }
 
     ret = create_resampler(DEFAULT_OUT_SAMPLING_RATE,
@@ -3297,11 +3314,11 @@ static int adev_open_output_stream(struct audio_hw_device *dev,
     out->stream.common.get_parameters = out_get_parameters;
     out->stream.common.add_audio_effect = out_add_audio_effect;
     out->stream.common.remove_audio_effect = out_remove_audio_effect;
-    out->stream.set_volume = out_set_volume;
     out->stream.get_render_position = out_get_render_position;
 
     out->dev = ladev;
     out->standby = 1;
+    /* out->muted = false; by calloc() */
 
     /* FIXME: when we support multiple output devices, we will want to
      * do the following: