Hosted PCM: Rework auto-muting code a bit

     * If AUDIOHW_MUTE_ON_PAUSE, no meaningful change
     * Unconditionally unmute on playback start
     * xduoox3ii:  Mute on sample rate change
     * rocker/xduoo:  Stay muted after startup

    This avoids the nasty "pop" on startup, without doing
    the full mute-on-pause stuff that causes unacceptable
    dropouts on the X3ii.

Change-Id: I2e3ee0bb8094e288f37a0acada86a80016ce5cac

5 files changed, 44 insertions, 22 deletions

diff --git a/firmware/drivers/audio/erosqlinux_codec.c b/firmware/drivers/audio/erosqlinux_codec.c
index deb3bb4b87..9336083d58 100644
--- a/firmware/drivers/audio/erosqlinux_codec.c
+++ b/firmware/drivers/audio/erosqlinux_codec.c
@@ -56,6 +56,8 @@ static void hw_close(void)
     close(fd_hw);
 }
 
+static int muted = -1;
+
 void audiohw_mute(int mute)
 {
     logf("mute %d", mute);
@@ -70,6 +72,7 @@ void audiohw_mute(int mute)
         last_ps = 0;
         erosq_get_outputs();
     }
+    muted = mute;
 }
 
 int erosq_get_outputs(void) {
@@ -95,7 +98,7 @@ int erosq_get_outputs(void) {
 
 void erosq_set_output(int ps)
 {
-    if (!inited) return;
+    if (!inited || muted) return;
 
     if (last_ps != ps)
     {
@@ -119,7 +122,7 @@ void audiohw_preinit(void)
 void audiohw_postinit(void)
 {
     logf("hw postinit");
-    erosq_set_output(erosq_get_outputs());  /* Unmute */
+    erosq_get_outputs(); // Unmutes
 }
 
 void audiohw_close(void)
diff --git a/firmware/drivers/audio/rocker_codec.c b/firmware/drivers/audio/rocker_codec.c
index 525507494b..e5573df843 100644
--- a/firmware/drivers/audio/rocker_codec.c
+++ b/firmware/drivers/audio/rocker_codec.c
@@ -70,7 +70,7 @@ void audiohw_postinit(void)
     long int hp = 2;
 
     /* Output port switch set to Headphones */
-    alsa_controls_set_ints("Output Port Switch", 1, &hp); /* Unmutes */
+    //alsa_controls_set_ints("Output Port Switch", 1, &hp); // Unmute happens on PCM start
 }
 
 void audiohw_close(void)
diff --git a/firmware/drivers/audio/xduoolinux_codec.c b/firmware/drivers/audio/xduoolinux_codec.c
index b114b1bbc9..59ef562d0a 100644
--- a/firmware/drivers/audio/xduoolinux_codec.c
+++ b/firmware/drivers/audio/xduoolinux_codec.c
@@ -55,6 +55,8 @@ static void hw_close(void)
     close(fd_hw);
 }
 
+static int muted = -1;
+
 void audiohw_mute(int mute)
 {
     logf("mute %d", mute);
@@ -69,6 +71,7 @@ void audiohw_mute(int mute)
         last_ps = 0;
         xduoo_get_outputs();
     }
+    muted = mute;
 }
 
 int xduoo_get_outputs(void){
@@ -102,7 +105,7 @@ int xduoo_get_outputs(void){
 
 void xduoo_set_output(int ps)
 {
-    if (!inited) return;
+    if (!inited || muted) return;
 
     if (last_ps != ps)
     {
@@ -128,7 +131,7 @@ void audiohw_postinit(void)
 //    const char * const codec_pmdown = "/sys/devices/platform/ingenic-x3ii.0/x3ii-ak4490-i2s/pmdown_time";  // in ms, defaults 5000
 
     logf("hw postinit");
-    xduoo_set_output(xduoo_get_outputs());  /* Unmute */
+    // xduoo_get_outputs(); // Unmute happens upon playback.
 }
 
 void audiohw_close(void)
diff --git a/firmware/export/xduoolinux_codec.h b/firmware/export/xduoolinux_codec.h
index a46976d386..09609d477c 100644
--- a/firmware/export/xduoolinux_codec.h
+++ b/firmware/export/xduoolinux_codec.h
@@ -6,6 +6,14 @@ AUDIOHW_SETTING(VOLUME, "dB", 0, 1, -127,  0, -30)
 AUDIOHW_SETTING(FILTER_ROLL_OFF, "", 0, 1, 0, 4, 0)
 #endif
 
+// We want this, but the codec takes over a second to unmute!
+//#define AUDIOHW_MUTE_ON_PAUSE
+
+#if defined(XDUOO_X3II)
+/* The AK4490 glitches when switching sample rates */
+#define AUDIOHW_MUTE_ON_SRATE_CHANGE
+#endif
+
 void audiohw_mute(int mute);
 void xduoo_set_output(int ps);
 int xduoo_get_outputs(void);
diff --git a/firmware/target/hosted/pcm-alsa.c b/firmware/target/hosted/pcm-alsa.c
index 3d91bc18cf..428902b82e 100644
--- a/firmware/target/hosted/pcm-alsa.c
+++ b/firmware/target/hosted/pcm-alsa.c
@@ -81,8 +81,8 @@ static const snd_pcm_format_t format = SND_PCM_FORMAT_S16;    /* sample format *
 typedef short sample_t;
 #endif
 static const int channels = 2;                                /* count of channels */
-static unsigned int sample_rate = 0;
 static unsigned int real_sample_rate = 0;
+static unsigned int last_sample_rate = 0;
 
 static snd_pcm_t *handle = NULL;
 static snd_pcm_sframes_t buffer_size;
@@ -148,17 +148,17 @@ static int set_hwparams(snd_pcm_t *handle)
         goto error;
     }
     /* set the stream rate */
-    sample_rate = srate = pcm_sampr;
+    srate = pcm_sampr;
     err = snd_pcm_hw_params_set_rate_near(handle, params, &srate, 0);
     if (err < 0)
     {
-        logf("Rate %iHz not available for playback: %s\n", sample_rate, snd_strerror(err));
+        logf("Rate %iHz not available for playback: %s\n", pcm_sampr, snd_strerror(err));
         goto error;
     }
     real_sample_rate = srate;
-    if (real_sample_rate != sample_rate)
+    if (real_sample_rate != pcm_sampr)
     {
-        logf("Rate doesn't match (requested %iHz, get %iHz)\n", sample_rate, real_sample_rate);
+        logf("Rate doesn't match (requested %iHz, get %iHz)\n", pcm_sampr, real_sample_rate);
         err = -EINVAL;
         goto error;
     }
@@ -517,11 +517,13 @@ void pcm_play_unlock(void)
 
 static void pcm_dma_apply_settings_nolock(void)
 {
-    logf("PCM DMA Settings %d %d", sample_rate, pcm_sampr);
+    logf("PCM DMA Settings %d %d", last_sample_rate, pcm_sampr);
 
-    if (sample_rate != pcm_sampr)
+    if (last_sample_rate != pcm_sampr)
     {
-#ifdef AUDIOHW_MUTE_ON_PAUSE
+	last_sample_rate = pcm_sampr;
+
+#ifdef AUDIOHW_MUTE_ON_SRATE_CHANGE
         // XXX AK4450 (xDuoo X3ii) needs to be muted when switching rates.
         audiohw_mute(true);
 #endif
@@ -531,8 +533,10 @@ static void pcm_dma_apply_settings_nolock(void)
         /* Sony NWZ linux driver uses a nonstandard mecanism to set the sampling rate */
         audiohw_set_frequency(pcm_sampr);
 #endif
-
-	/* (Will be unmuted by pcm resuming) */
+#ifdef AUDIOHW_MUTE_ON_SRATE_CHANGE
+        audiohw_mute(false);
+#endif
+        /* (Will be unmuted by pcm resuming) */
     }
 }
 
@@ -560,7 +564,7 @@ void pcm_play_dma_stop(void)
     snd_pcm_nonblock(handle, 0);
     snd_pcm_drain(handle);
     snd_pcm_nonblock(handle, 1);
-    sample_rate = 0;
+    last_sample_rate = 0;
 #ifdef AUDIOHW_MUTE_ON_PAUSE
     audiohw_mute(true);
 #endif
@@ -575,6 +579,10 @@ void pcm_play_dma_start(const void *addr, size_t size)
     pcm_data = addr;
     pcm_size = size;
 
+#if !defined(AUDIOHW_MUTE_ON_PAUSE) || !defined(AUDIOHW_MUTE_ON_SRATE_CHANGE)
+    audiohw_mute(false);
+#endif
+
     while (1)
     {
         snd_pcm_state_t state = snd_pcm_state(handle);
@@ -605,14 +613,14 @@ void pcm_play_dma_start(const void *addr, size_t size)
                 int err = async_rw(handle);
                 if (err < 0) {
                     logf("Start error: %s\n", snd_strerror(err));
-		    return;
-		}
+                    return;
+                }
 #ifdef AUDIOHW_MUTE_ON_PAUSE
-    audiohw_mute(false);
+                audiohw_mute(false);
 #endif
-		if (err == 0)
-			return;
-		break;
+                if (err == 0)
+                    return;
+                break;
             }
             case SND_PCM_STATE_PAUSED:
             {   /* paused, simply resume */