From afa7ebc03250481bd36ff98bb5bf3106c68f6af1 Mon Sep 17 00:00:00 2001
From: Sanchayan Maity <sanchayan@asymptotic.io>
Date: Tue, 6 May 2025 16:13:40 +0530
Subject: [PATCH] media-sink: Drop packet if send fails for ASHA

One of the ideas behind retrying the sending of a failed packet with the
poll callback was to make sure that we do not end up with missing seqnums
by missing received credit due to some jitter.

However, the rate matching behaviour for ASHA is not clear and we do not
seem to face problems in local testing by just dropping the packet.
---
 spa/plugins/bluez5/media-sink.c | 52 ---------------------------------
 1 file changed, 52 deletions(-)

diff --git a/spa/plugins/bluez5/media-sink.c b/spa/plugins/bluez5/media-sink.c
index e335889af..5bc1811dd 100644
--- a/spa/plugins/bluez5/media-sink.c
+++ b/spa/plugins/bluez5/media-sink.c
@@ -113,13 +113,11 @@ struct spa_bt_asha {
 	int timerfd;
 
 	uint8_t buf[512];
-	uint8_t seqnum_pending;
 
 	uint64_t ref_t0;
 	uint64_t next_time;
 
 	unsigned int flush_pending:1;
-	unsigned int poll_pending:1;
 	unsigned int set_timer:1;
 };
 
@@ -1354,16 +1352,6 @@ static void media_asha_flush_timeout(struct spa_source *source)
 
 	asha->next_time += (uint64_t)(ASHA_CONN_INTERVAL * port->ratectl.corr);
 
-	if (asha->poll_pending) {
-		/*
-		 * We have pending data to send but we could not send it
-		 * before the connection interval elapsed.
-		 */
-		asha->poll_pending = false;
-		spa_log_trace(this->log, "%p: ASHA failed to send seqnum %d for %s",
-				this, asha->seqnum_pending, address);
-	}
-
 	if (asha->flush_pending) {
 		asha->buf[0] = this->seqnum;
 		written = send(asha->flush_source.fd, asha->buf,
@@ -1371,19 +1359,9 @@ static void media_asha_flush_timeout(struct spa_source *source)
 		/*
 		 * For ASHA, when we are out of LE credits and cannot write to
 		 * the socket, return value of `send` will be -EAGAIN.
-		 *
-		 *  If we fail to send here, send on the next `poll` which
-		 *  ideally will be a few ms away on receiving LE credits. We
-		 *  cannot delay the flush till the next cycle.
 		 */
 		if (written < 0) {
-			asha->seqnum_pending = seqnum;
-			asha->poll_pending = true;
 			asha->flush_pending = false;
-
-			SPA_FLAG_UPDATE(asha->flush_source.mask, SPA_IO_OUT, 1);
-			spa_loop_update_source(this->data_loop, &asha->flush_source);
-
 			spa_log_warn(this->log, "%p: ASHA failed to flush %d seqnum on timer for %s, written:%d",
 					this, this->seqnum, address, -errno);
 			goto skip_flush;
@@ -1409,8 +1387,6 @@ static void media_asha_cb(struct spa_source *source)
 	struct impl *this = source->data;
 	struct spa_bt_asha *asha = this->asha;
 	const char *address = this->transport->device->address;
-	uint8_t seqnum;
-	int written;
 
 	if (source->rmask & (SPA_IO_HUP | SPA_IO_ERR)) {
 		spa_log_error(this->log, "%p: ASHA source error %d on %s", this, source->rmask, address);
@@ -1420,33 +1396,6 @@ static void media_asha_cb(struct spa_source *source)
 
 		return;
 	}
-
-	if (source->rmask & SPA_IO_OUT) {
-		if (this->transport == NULL || !asha->poll_pending) {
-			return;
-		}
-
-		SPA_FLAG_UPDATE(asha->flush_source.mask, SPA_IO_OUT, 0);
-		spa_loop_update_source(this->data_loop, &asha->flush_source);
-
-		seqnum = asha->buf[0];
-		written = send(asha->flush_source.fd, asha->buf,
-				ASHA_ENCODED_PKT_SZ, MSG_DONTWAIT | MSG_NOSIGNAL);
-		/*
-		 * For ASHA, when we are out of LE credits and cannot write to
-		 * the socket, return value of `send` will be -EAGAIN.
-		 */
-		if (written < 0) {
-			spa_log_warn(this->log, "%p: ASHA failed to flush %d seqnum on poll for %s, written:%d",
-					this, seqnum, address, -errno);
-		}
-
-		if (written > 0) {
-			asha->poll_pending = false;
-			spa_log_trace(this->log, "%p: ASHA flush %d seqnum for %s",
-					this, seqnum, address);
-		}
-	}
 }
 
 static int do_start_iso_io(struct spa_loop *loop, bool async, uint32_t seq,
@@ -1576,7 +1525,6 @@ static int transport_start(struct impl *this)
 		struct spa_bt_asha *asha = this->asha;
 
 		asha->flush_pending = false;
-		asha->poll_pending = false;
 		asha->set_timer = false;
 
 		asha->timer_source.data = this;