3 files changed, 41 insertions, 1 deletions
diff --git a/sound/firewire/tascam/amdtp-tascam.c b/sound/firewire/tascam/amdtp-tascam.c
index 516cb931fd5e..0e8088c9ada9 100644
--- a/sound/firewire/tascam/amdtp-tascam.c
+++ b/sound/firewire/tascam/amdtp-tascam.c
@@ -121,13 +121,45 @@ static void read_status_messages(struct amdtp_stream *s,
 				 __be32 *buffer, unsigned int data_blocks)
 {
 	struct snd_tscm *tscm = container_of(s, struct snd_tscm, tx_stream);
+	bool used = READ_ONCE(tscm->hwdep->used);
 	int i;
 
 	for (i = 0; i < data_blocks; i++) {
 		unsigned int index;
+		__be32 before;
+		__be32 after;
 
 		index = be32_to_cpu(buffer[0]) % SNDRV_FIREWIRE_TASCAM_STATE_COUNT;
-		tscm->state[index] = buffer[s->data_block_quadlets - 1];
+		before = tscm->state[index];
+		after = buffer[s->data_block_quadlets - 1];
+
+		if (used && index > 4 && index < 16) {
+			__be32 mask;
+
+			if (index == 5)
+				mask = cpu_to_be32(~0x0000ffff);
+			else if (index == 6)
+				mask = cpu_to_be32(~0x0000ffff);
+			else if (index == 8)
+				mask = cpu_to_be32(~0x000f0f00);
+			else
+				mask = cpu_to_be32(~0x00000000);
+
+			if ((before ^ after) & mask) {
+				struct snd_firewire_tascam_change *entry =
+						&tscm->queue[tscm->push_pos];
+
+				spin_lock_irq(&tscm->lock);
+				entry->index = index;
+				entry->before = before;
+				entry->after = after;
+				if (++tscm->push_pos >= SND_TSCM_QUEUE_COUNT)
+					tscm->push_pos = 0;
+				spin_unlock_irq(&tscm->lock);
+			}
+		}
+
+		tscm->state[index] = after;
 		buffer += s->data_block_quadlets;
 	}
 }
diff --git a/sound/firewire/tascam/tascam-hwdep.c b/sound/firewire/tascam/tascam-hwdep.c
index a80397116c48..9afa827af05d 100644
--- a/sound/firewire/tascam/tascam-hwdep.c
+++ b/sound/firewire/tascam/tascam-hwdep.c
@@ -195,5 +195,7 @@ int snd_tscm_create_hwdep_device(struct snd_tscm *tscm)
 	hwdep->private_data = tscm;
 	hwdep->exclusive = true;
 
+	tscm->hwdep = hwdep;
+
 	return err;
 }
diff --git a/sound/firewire/tascam/tascam.h b/sound/firewire/tascam/tascam.h
index c710496a99cf..6a411ee0dcf1 100644
--- a/sound/firewire/tascam/tascam.h
+++ b/sound/firewire/tascam/tascam.h
@@ -62,6 +62,8 @@ struct snd_fw_async_midi_port {
 	int consume_bytes;
 };
 
+#define SND_TSCM_QUEUE_COUNT	16
+
 struct snd_tscm {
 	struct snd_card *card;
 	struct fw_unit *unit;
@@ -92,6 +94,10 @@ struct snd_tscm {
 
 	// A cache of status information in tx isoc packets.
 	__be32 state[SNDRV_FIREWIRE_TASCAM_STATE_COUNT];
+	struct snd_hwdep *hwdep;
+	struct snd_firewire_tascam_change queue[SND_TSCM_QUEUE_COUNT];
+	unsigned int pull_pos;
+	unsigned int push_pos;
 };
 
 #define TSCM_ADDR_BASE			0xffff00000000ull