Update volume when changing soft-volume property

src/ba-rfcomm.c

@@ -440,14 +440,14 @@ static int rfcomm_handler_vgm_set_cb(struct ba_rfcomm *r, const struct bt_at *at
 
 	struct ba_transport * const t_sco = r->sco;
 	struct ba_transport_pcm *pcm = &t_sco->sco.pcm_mic;
+	const int gain = r->gain_mic = atoi(at->value);
 	const int fd = r->fd;
 
 	/* skip update in case of software volume */
 	if (pcm->soft_volume)
 		return rfcomm_write_at(fd, AT_TYPE_RESP, NULL, "OK");
 
-	r->gain_mic = atoi(at->value);
-	int level = ba_transport_pcm_volume_range_to_level(r->gain_mic, HFP_VOLUME_GAIN_MAX);
+	int level = ba_transport_pcm_volume_range_to_level(gain, HFP_VOLUME_GAIN_MAX);
 
 	pthread_mutex_lock(&pcm->mutex);
 	ba_transport_pcm_volume_set(&pcm->volume[0], &level, NULL, NULL);
@@ -467,8 +467,8 @@ static int rfcomm_handler_vgm_resp_cb(struct ba_rfcomm *r, const struct bt_at *a
 	struct ba_transport * const t_sco = r->sco;
 	struct ba_transport_pcm *pcm = &t_sco->sco.pcm_mic;
 
-	r->gain_mic = atoi(at->value);
-	int level = ba_transport_pcm_volume_range_to_level(r->gain_mic, HFP_VOLUME_GAIN_MAX);
+	int gain = r->gain_mic = atoi(at->value);
+	int level = ba_transport_pcm_volume_range_to_level(gain, HFP_VOLUME_GAIN_MAX);
 
 	pthread_mutex_lock(&pcm->mutex);
 	ba_transport_pcm_volume_set(&pcm->volume[0], &level, NULL, NULL);
@@ -485,14 +485,14 @@ static int rfcomm_handler_vgs_set_cb(struct ba_rfcomm *r, const struct bt_at *at
 
 	struct ba_transport * const t_sco = r->sco;
 	struct ba_transport_pcm *pcm = &t_sco->sco.pcm_spk;
+	const int gain = r->gain_spk = atoi(at->value);
 	const int fd = r->fd;
 
 	/* skip update in case of software volume */
 	if (pcm->soft_volume)
 		return rfcomm_write_at(fd, AT_TYPE_RESP, NULL, "OK");
 
-	r->gain_spk = atoi(at->value);
-	int level = ba_transport_pcm_volume_range_to_level(r->gain_spk, HFP_VOLUME_GAIN_MAX);
+	int level = ba_transport_pcm_volume_range_to_level(gain, HFP_VOLUME_GAIN_MAX);
 
 	pthread_mutex_lock(&pcm->mutex);
 	ba_transport_pcm_volume_set(&pcm->volume[0], &level, NULL, NULL);
@@ -512,8 +512,8 @@ static int rfcomm_handler_vgs_resp_cb(struct ba_rfcomm *r, const struct bt_at *a
 	struct ba_transport * const t_sco = r->sco;
 	struct ba_transport_pcm *pcm = &t_sco->sco.pcm_spk;
 
-	r->gain_spk = atoi(at->value);
-	int level = ba_transport_pcm_volume_range_to_level(r->gain_spk, HFP_VOLUME_GAIN_MAX);
+	int gain = r->gain_spk = atoi(at->value);
+	int level = ba_transport_pcm_volume_range_to_level(gain, HFP_VOLUME_GAIN_MAX);
 
 	pthread_mutex_lock(&pcm->mutex);
 	ba_transport_pcm_volume_set(&pcm->volume[0], &level, NULL, NULL);

src/ba-transport-pcm.c

@@ -35,6 +35,7 @@
 #include "bluez-iface.h"
 #include "bluez.h"
 #include "dbus.h"
+#include "hfp.h"
 #include "io.h"
 #if ENABLE_OFONO
 # include "ofono.h"
@@ -693,6 +694,33 @@ int ba_transport_pcm_volume_update(struct ba_transport_pcm *pcm) {
 	return 0;
 }
 
+/**
+ * Get non-software PCM volume level if available. */
+int ba_transport_pcm_get_hardware_volume(
+		const struct ba_transport_pcm *pcm) {
+
+	const struct ba_transport *t = pcm->t;
+
+	if (t->profile & BA_TRANSPORT_PROFILE_MASK_A2DP)
+		return t->a2dp.volume;
+
+	if (t->profile & BA_TRANSPORT_PROFILE_MASK_SCO) {
+
+		if (t->sco.rfcomm == NULL)
+			/* TODO: Cache volume level for oFono-based SCO */
+			return HFP_VOLUME_GAIN_MAX;
+
+		if (pcm == &t->sco.pcm_spk)
+			return t->sco.rfcomm->gain_spk;
+		if (pcm == &t->sco.pcm_mic)
+			return t->sco.rfcomm->gain_mic;
+
+	}
+
+	g_assert_not_reached();
+	return 0;
+}
+
 int ba_transport_pcm_get_delay(const struct ba_transport_pcm *pcm) {
 
 	const struct ba_transport *t = pcm->t;

src/ba-transport-pcm.h

@@ -250,6 +250,9 @@ void ba_transport_pcm_volume_set(
 int ba_transport_pcm_volume_update(
 		struct ba_transport_pcm *pcm);
 
+int ba_transport_pcm_get_hardware_volume(
+		const struct ba_transport_pcm *pcm);
+
 int ba_transport_pcm_get_delay(
 		const struct ba_transport_pcm *pcm);
 

src/bluealsa-dbus.c

@@ -1023,18 +1023,38 @@ static bool bluealsa_pcm_set_property(const char *property, GVariant *value,
 		GError **error, void *userdata) {
 
 	struct ba_transport_pcm *pcm = userdata;
+	struct ba_transport *t = pcm->t;
+
+	const bool is_sco = t->profile & BA_TRANSPORT_PROFILE_MASK_SCO;
+	const int volume_max = is_sco ? HFP_VOLUME_GAIN_MAX : BLUEZ_A2DP_VOLUME_MAX;
 
 	if (strcmp(property, "SoftVolume") == 0) {
-		pcm->soft_volume = g_variant_get_boolean(value);
-		bluealsa_dbus_pcm_update(pcm, BA_DBUS_PCM_UPDATE_SOFT_VOLUME);
+
+		const bool soft_volume = g_variant_get_boolean(value);
+
+		/* In case when the software volume was just enabled, set the volume level
+		 * to the maximum. This will prevent volume change during the transition.
+		 * In case of disabling the software volume, we will restore the hardware
+		 * volume level, so the volume control will indicate the correct level. */
+		const int volume = soft_volume ? volume_max : ba_transport_pcm_get_hardware_volume(pcm);
+		const int level = ba_transport_pcm_volume_range_to_level(volume, volume_max);
+
+		pthread_mutex_lock(&pcm->mutex);
+
+		debug("Setting software volume: %s", soft_volume ? "true" : "false");
+		pcm->soft_volume = soft_volume;
+
+		for (size_t i = 0; i < pcm->channels; i++)
+			ba_transport_pcm_volume_set(&pcm->volume[i], &level, NULL, NULL);
+
+		pthread_mutex_unlock(&pcm->mutex);
+
+		bluealsa_dbus_pcm_update(pcm, BA_DBUS_PCM_UPDATE_SOFT_VOLUME | BA_DBUS_PCM_UPDATE_VOLUME);
 		return true;
 	}
 
 	if (strcmp(property, "Volume") == 0) {
 
-		const bool is_sco = pcm->t->profile & BA_TRANSPORT_PROFILE_MASK_SCO;
-		const int max = is_sco ? HFP_VOLUME_GAIN_MAX : BLUEZ_A2DP_VOLUME_MAX;
-
 		size_t channels = 0;
 		const uint8_t *volume = g_variant_get_fixed_array(value, &channels, sizeof(uint8_t));
 
@@ -1049,11 +1069,10 @@ static bool bluealsa_pcm_set_property(const char *property, GVariant *value,
 		for (size_t i = 0; i < channels; i++) {
 
 			const bool muted = !!(volume[i] & 0x80);
-			const int level = ba_transport_pcm_volume_range_to_level(volume[i] & 0x7F, max);
+			const int level = ba_transport_pcm_volume_range_to_level(volume[i] & 0x7F, volume_max);
 
 			debug("Setting volume [ch=%zu]: %u [%.2f dB] [%c]",
 					i, volume[i] & 0x7F, 0.01 * level, muted ? 'x' : ' ');
-
 			ba_transport_pcm_volume_set(&pcm->volume[i], &level, &muted, NULL);
 
 		}