ALSA: firewire-lib: remove rx_blocks_for_midi quirk

There are several devices that expect to receive MIDI data only in the
first eight data blocks of a packet.  If the driver restricts the data
rate to the allowed rate (as mandated by the specification, but not yet
implemented by this driver), this happens naturally.  Therefore, there
is no reason to ever try to use more data packets with any device.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Tested-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/amdtp.c

@@ -21,7 +21,13 @@
 #define CYCLES_PER_SECOND	8000
 #define TICKS_PER_SECOND	(TICKS_PER_CYCLE * CYCLES_PER_SECOND)
 
-#define TRANSFER_DELAY_TICKS	0x2e00 /* 479.17 µs */
+/*
+ * Several devices look only at the first eight data blocks.
+ * In any case, this is more than enough for the MIDI data rate.
+ */
+#define MAX_MIDI_RX_BLOCKS	8
+
+#define TRANSFER_DELAY_TICKS	0x2e00 /* 479.17 µs */
 
 /* isochronous header parameters */
 #define ISO_DATA_LENGTH_SHIFT	16
@@ -78,8 +84,6 @@ 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);
@@ -474,7 +478,7 @@ static void amdtp_fill_midi(struct amdtp_stream *s,
 		b = (u8 *)&buffer[s->midi_position];
 
 		port = (s->data_block_counter + f) % 8;
-		if ((f >= s->rx_blocks_for_midi) ||
+		if ((f >= MAX_MIDI_RX_BLOCKS) ||
 		    (s->midi[port] == NULL) ||
 		    (snd_rawmidi_transmit(s->midi[port], b + 1, 1) <= 0))
 			b[0] = 0x80;

sound/firewire/amdtp.h

@@ -152,9 +152,6 @@ 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/bebob/bebob_stream.c

@@ -484,13 +484,6 @@ int snd_bebob_stream_init_duplex(struct snd_bebob *bebob)
 		amdtp_stream_destroy(&bebob->rx_stream);
 		destroy_both_connections(bebob);
 	}
-	/*
-	 * The firmware for these devices ignore MIDI messages in more than
-	 * first 8 data blocks of an received AMDTP packet.
-	 */
-	if (bebob->spec == &maudio_fw410_spec ||
-	    bebob->spec == &maudio_special_spec)
-		bebob->rx_stream.rx_blocks_for_midi = 8;
 end:
 	return err;
 }

sound/firewire/fireworks/fireworks_stream.c

@@ -179,11 +179,6 @@ 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);