pulse-server: track quantum and update tlength

Keep track of the current quantum and recalculate the tlength in the
same way that pulseaudio does.

Send a bufferattr changed message to a client when we change the
parameters.

This fixes the case where the quantum is increased and there needs to be
more buffering to keep the stream going.

src/modules/module-protocol-pulse/pulse-server.c

@@ -1089,6 +1089,9 @@ static void stream_io_changed(void *data, uint32_t id, void *area, uint32_t size
 	case SPA_IO_RateMatch:
 		stream->rate_match = area;
 		break;
+	case SPA_IO_Position:
+		stream->position = area;
+		break;
 	}
 }
 
@@ -1099,7 +1102,8 @@ struct process_data {
 	uint32_t underrun_for;
 	uint32_t playing_for;
 	uint32_t missing;
-	uint32_t maxmissing;
+	uint32_t minreq;
+	uint32_t quantum;
 	unsigned int underrun:1;
 };
 
@@ -1121,6 +1125,10 @@ do_process_done(struct spa_loop *loop,
 		stream->delay = 0;
 
 	if (stream->direction == PW_DIRECTION_OUTPUT) {
+		if (stream->last_quantum != 0 && pd->quantum != stream->last_quantum)
+			stream_update_minreq(stream, pd->minreq);
+		stream->last_quantum = pd->quantum;
+
 		stream->read_index += pd->read_inc;
 		if (stream->corked) {
 			if (stream->underrun_for != (uint64_t)-1)
@@ -1138,7 +1146,7 @@ do_process_done(struct spa_loop *loop,
 				stream_send_started(stream);
 		}
 		stream->missing += pd->missing;
-		stream->missing = SPA_MIN(stream->missing, pd->maxmissing);
+		stream->missing = SPA_MIN(stream->missing, (int64_t)stream->attr.tlength);
 		stream->playing_for += pd->playing_for;
 		if (stream->underrun_for != (uint64_t)-1)
 			stream->underrun_for += pd->underrun_for;
@@ -1232,7 +1240,8 @@ static void stream_process(void *data)
 		if (minreq == 0)
 			minreq = stream->attr.minreq;
 
-		pd.maxmissing = SPA_MAX(minreq, stream->attr.tlength);
+		pd.minreq = minreq;
+		pd.quantum = stream->position ? stream->position->clock.duration : minreq;
 
 		if (avail < (int32_t)minreq || stream->corked) {
 			/* underrun, produce a silence buffer */

src/modules/module-protocol-pulse/stream.c

@@ -256,3 +256,42 @@ int stream_send_request(struct stream *stream)
 
 	return client_queue_message(client, msg);
 }
+
+int stream_update_minreq(struct stream *stream, uint32_t minreq)
+{
+	struct client *client = stream->client;
+	struct impl *impl = client->impl;
+	uint32_t old_tlength = stream->attr.tlength;
+	uint32_t new_tlength = minreq + 2 * stream->attr.minreq;
+	uint64_t lat_usec;
+
+	if (new_tlength == old_tlength)
+		return 0;
+
+	if (old_tlength > new_tlength)
+		stream->missing -= old_tlength - new_tlength;
+	else
+		stream->missing += new_tlength - old_tlength;
+
+	stream->attr.tlength = new_tlength;
+
+	if (client->version >= 15) {
+		struct message *msg;
+
+		lat_usec = minreq * SPA_USEC_PER_SEC / stream->ss.rate;
+
+		msg = message_alloc(impl, -1, 0);
+		message_put(msg,
+			TAG_U32, COMMAND_PLAYBACK_BUFFER_ATTR_CHANGED,
+			TAG_U32, -1,
+			TAG_U32, stream->channel,
+			TAG_U32, stream->attr.maxlength,
+			TAG_U32, stream->attr.tlength,
+			TAG_U32, stream->attr.prebuf,
+			TAG_U32, stream->attr.minreq,
+			TAG_USEC, lat_usec,
+			TAG_INVALID);
+		return client_queue_message(client, msg);
+	}
+	return 0;
+}

src/modules/module-protocol-pulse/stream.h

@@ -67,6 +67,7 @@ struct stream {
 	struct spa_hook stream_listener;
 
 	struct spa_io_rate_match *rate_match;
+	struct spa_io_position *position;
 	struct spa_ringbuffer ring;
 	void *buffer;
 
@@ -78,8 +79,9 @@ struct stream {
 	uint64_t timestamp;
 	int64_t delay;
 
-	uint32_t missing;
-	uint32_t requested;
+	uint32_t last_quantum;
+	int64_t missing;
+	int64_t requested;
 
 	struct sample_spec ss;
 	struct channel_map map;
@@ -112,5 +114,6 @@ int stream_send_overflow(struct stream *stream);
 int stream_send_killed(struct stream *stream);
 int stream_send_started(struct stream *stream);
 int stream_send_request(struct stream *stream);
+int stream_update_minreq(struct stream *stream, uint32_t minreq);
 
 #endif /* PULSER_SERVER_STREAM_H */