ALSA: firewire-lib: split allocation of isochronous resources from establishment of connection

In current implementation, establishment connection corresponds to
allocation of isochronous resources. Although this is an ideal
implementation of CMP described in IEC 61883-1, it's not enough
efficient to recover PCM substream multiplexed in packet streaming.
The packet streaming can always restart on the same allocated
isochronous resources even if the previous packet streaming
corrupted.

This commit splits allocation of isochronous resources from
establishment of connection so that CMP runs with allocated
isochronous resources.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 14 insertions, 4 deletions

diff --git a/sound/firewire/oxfw/oxfw-stream.c b/sound/firewire/oxfw/oxfw-stream.c
index 837733f10736..a8bc798731ff 100644
--- a/sound/firewire/oxfw/oxfw-stream.c
+++ b/sound/firewire/oxfw/oxfw-stream.c
@@ -111,8 +111,7 @@ static int start_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
 	else
 		conn = &oxfw->out_conn;
 
-	err = cmp_connection_establish(conn,
-				       amdtp_stream_get_max_payload(stream));
+	err = cmp_connection_establish(conn);
 	if (err < 0)
 		return err;
 
@@ -203,15 +202,18 @@ static int keep_resources(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
 	enum avc_general_plug_dir dir;
 	u8 **formats;
 	struct snd_oxfw_stream_formation formation;
+	struct cmp_connection *conn;
 	int i;
 	int err;
 
 	if (stream == &oxfw->rx_stream) {
 		dir = AVC_GENERAL_PLUG_DIR_IN;
 		formats = oxfw->rx_stream_formats;
+		conn = &oxfw->in_conn;
 	} else {
 		dir = AVC_GENERAL_PLUG_DIR_OUT;
 		formats = oxfw->tx_stream_formats;
+		conn = &oxfw->out_conn;
 	}
 
 	err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
@@ -239,8 +241,12 @@ static int keep_resources(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
 	if (formation.pcm == 0)
 		return -EINVAL;
 
-	return amdtp_am824_set_parameters(stream, formation.rate, formation.pcm,
+	err = amdtp_am824_set_parameters(stream, formation.rate, formation.pcm,
 					 formation.midi * 8, false);
+	if (err < 0)
+		return err;
+
+	return cmp_connection_reserve(conn, amdtp_stream_get_max_payload(stream));
 }
 
 int snd_oxfw_stream_reserve_duplex(struct snd_oxfw *oxfw,
@@ -299,8 +305,10 @@ int snd_oxfw_stream_reserve_duplex(struct snd_oxfw *oxfw,
 
 		if (oxfw->has_output) {
 			err = keep_resources(oxfw, &oxfw->tx_stream);
-			if (err < 0)
+			if (err < 0) {
+				cmp_connection_release(&oxfw->in_conn);
 				return err;
+			}
 		}
 	}
 
@@ -361,10 +369,12 @@ void snd_oxfw_stream_stop_duplex(struct snd_oxfw *oxfw)
 	if (oxfw->substreams_count == 0) {
 		amdtp_stream_stop(&oxfw->rx_stream);
 		cmp_connection_break(&oxfw->in_conn);
+		cmp_connection_release(&oxfw->in_conn);
 
 		if (oxfw->has_output) {
 			amdtp_stream_stop(&oxfw->tx_stream);
 			cmp_connection_break(&oxfw->out_conn);
+			cmp_connection_release(&oxfw->out_conn);
 		}
 	}
 }