ALSA: fireworks/firewire-lib: Add a quirk of data blocks for MIDI in out-stream

Fireworks has a quirk to ignore MIDI messages in data blocks more than 8.
This commit adds a flag for this quirk and codes to skip 8 or more data
blocks to transfer MIDI messages.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/firewire/amdtp.c

@@ -78,6 +78,8 @@ int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
 	s->callbacked = false;
 	s->sync_slave = NULL;
 
+	s->rx_blocks_for_midi = UINT_MAX;
+
 	return 0;
 }
 EXPORT_SYMBOL(amdtp_stream_init);
@@ -472,7 +474,8 @@ static void amdtp_fill_midi(struct amdtp_stream *s,
 		b = (u8 *)&buffer[s->midi_position];
 
 		port = (s->data_block_counter + f) % 8;
-		if ((s->midi[port] == NULL) ||
+		if ((f >= s->rx_blocks_for_midi) ||
+		    (s->midi[port] == NULL) ||
 		    (snd_rawmidi_transmit(s->midi[port], b + 1, 1) <= 0))
 			b[0] = 0x80;
 		else

sound/firewire/amdtp.h

@@ -125,6 +125,9 @@ struct amdtp_stream {
 	/* quirk: fixed interval of dbc between previos/current packets. */
 	unsigned int tx_dbc_interval;
 
+	/* quirk: the first count of data blocks in an rx packet for MIDI */
+	unsigned int rx_blocks_for_midi;
+
 	bool callbacked;
 	wait_queue_head_t callback_wait;
 	struct amdtp_stream *sync_slave;

sound/firewire/fireworks/fireworks_stream.c

@@ -212,6 +212,11 @@ int snd_efw_stream_init_duplex(struct snd_efw *efw)
 		destroy_stream(efw, &efw->tx_stream);
 		goto end;
 	}
+	/*
+	 * Fireworks ignores MIDI messages in more than first 8 data
+	 * blocks of an received AMDTP packet.
+	 */
+	efw->rx_stream.rx_blocks_for_midi = 8;
 
 	/* set IEC61883 compliant mode (actually not fully compliant...) */
 	err = snd_efw_command_set_tx_mode(efw, SND_EFW_TRANSPORT_MODE_IEC61883);