5 files changed, 19 insertions, 4 deletions
diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index 39033876593..4a7cc1f77d8 100644
--- a/sound/firewire/amdtp.c
+++ b/sound/firewire/amdtp.c
@@ -618,7 +618,8 @@ static void handle_in_packet(struct amdtp_stream *s,
 			     __be32 *buffer)
 {
 	u32 cip_header[2];
-	unsigned int data_blocks, data_block_quadlets, data_block_counter;
+	unsigned int data_blocks, data_block_quadlets, data_block_counter,
+		     dbc_interval;
 	struct snd_pcm_substream *pcm = NULL;
 	bool lost;
 
@@ -661,11 +662,17 @@ static void handle_in_packet(struct amdtp_stream *s,
 
 	/* Check data block counter continuity */
 	data_block_counter = cip_header[0] & AMDTP_DBC_MASK;
-	if (!(s->flags & CIP_DBC_IS_END_EVENT))
+	if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
 		lost = data_block_counter != s->data_block_counter;
-	else
+	} else {
+		if ((data_blocks > 0) && (s->tx_dbc_interval > 0))
+			dbc_interval = s->tx_dbc_interval;
+		else
+			dbc_interval = data_blocks;
+
 		lost = data_block_counter !=
-		       ((s->data_block_counter + data_blocks) & 0xff);
+		       ((s->data_block_counter + dbc_interval) & 0xff);
+	}
 
 	if (lost) {
 		dev_info(&s->unit->device,
diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h
index f334ae51e44..05f1b8b30e2 100644
--- a/sound/firewire/amdtp.h
+++ b/sound/firewire/amdtp.h
@@ -119,6 +119,9 @@ struct amdtp_stream {
 
 	struct snd_rawmidi_substream *midi[AMDTP_MAX_CHANNELS_FOR_MIDI * 8];
 
+	/* quirk: fixed interval of dbc between previos/current packets. */
+	unsigned int tx_dbc_interval;
+
 	bool callbacked;
 	wait_queue_head_t callback_wait;
 	struct amdtp_stream *sync_slave;
diff --git a/sound/firewire/fireworks/fireworks.c b/sound/firewire/fireworks/fireworks.c
index 02b3259059f..25997f1ee30 100644
--- a/sound/firewire/fireworks/fireworks.c
+++ b/sound/firewire/fireworks/fireworks.c
@@ -84,6 +84,7 @@ get_hardware_info(struct snd_efw *efw)
 		 (hwinfo->arm_version >> 16) & 0xff);
 	if (err < 0)
 		goto end;
+	efw->firmware_version = hwinfo->arm_version;
 
 	strcpy(efw->card->driver, "Fireworks");
 	strcpy(efw->card->shortname, hwinfo->model_name);
diff --git a/sound/firewire/fireworks/fireworks.h b/sound/firewire/fireworks/fireworks.h
index 9534e93e3a3..3f998510ddf 100644
--- a/sound/firewire/fireworks/fireworks.h
+++ b/sound/firewire/fireworks/fireworks.h
@@ -63,6 +63,7 @@ struct snd_efw {
 
 	/* for quirks */
 	bool is_af9;
+	u32 firmware_version;
 
 	unsigned int midi_in_ports;
 	unsigned int midi_out_ports;
diff --git a/sound/firewire/fireworks/fireworks_stream.c b/sound/firewire/fireworks/fireworks_stream.c
index 7447af72ae3..c75c2ef2ae3 100644
--- a/sound/firewire/fireworks/fireworks_stream.c
+++ b/sound/firewire/fireworks/fireworks_stream.c
@@ -201,6 +201,9 @@ int snd_efw_stream_init_duplex(struct snd_efw *efw)
 	/* AudioFire9 always reports wrong dbs. */
 	if (efw->is_af9)
 		efw->tx_stream.flags |= CIP_WRONG_DBS;
+	/* Firmware version 5.5 reports fixed interval for dbc. */
+	if (efw->firmware_version == 0x5050000)
+		efw->tx_stream.tx_dbc_interval = 8;
 
 	err = init_stream(efw, &efw->rx_stream);
 	if (err < 0) {