Bluetooth: CAP: Add support for handling ASE errors

If we get an error/rejection from the CAP acceptor when
performing the Unicast Audio Start or Stop procedure then
we need to abort the procedure and let the application determine
what the next step is.

This change triggered a corner case when connecting to multiple
CAP acceptors as the CAP initiatior that was fixed as part
of this.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>

subsys/bluetooth/audio/bap_stream.c

@@ -699,7 +699,6 @@ int bt_bap_stream_enable(struct bt_bap_stream *stream, const uint8_t meta[], siz
 
 int bt_bap_stream_stop(struct bt_bap_stream *stream)
 {
-	enum bt_iso_state iso_state;
 	struct bt_bap_ep *ep;
 	uint8_t role;
 	int err;
@@ -726,27 +725,6 @@ int bt_bap_stream_stop(struct bt_bap_stream *stream)
 		return -EBADMSG;
 	}
 
-	/* ASCS_v1.0 3.2 ASE state machine transitions
-	 *
-	 * If the server detects link loss of a CIS for an ASE in the Streaming state or the
-	 * Disabling state, the server shall immediately transition that ASE to the QoS Configured
-	 * state.
-	 *
-	 * This effectively means that if an ASE no longer has a connected CIS, the server shall
-	 * bring it to the QoS Configured state. That means that we, as a unicast client, should not
-	 * attempt to stop it
-	 */
-	if (ep->iso == NULL) {
-		LOG_DBG("Stream endpoint does not have a CIS, server will stop the ASE");
-		return -EALREADY;
-	}
-
-	iso_state = ep->iso->chan.state;
-	if (iso_state != BT_ISO_STATE_CONNECTED && iso_state != BT_ISO_STATE_CONNECTING) {
-		LOG_DBG("Stream endpoint CIS is not connected, server will stop the ASE");
-		return -EALREADY;
-	}
-
 	err = bt_bap_unicast_client_stop(stream);
 	if (err != 0) {
 		LOG_DBG("Stopping stream failed: %d", err);

subsys/bluetooth/audio/bap_unicast_client.c

@@ -3481,6 +3481,7 @@ int bt_bap_unicast_client_disable(struct bt_bap_stream *stream)
 int bt_bap_unicast_client_stop(struct bt_bap_stream *stream)
 {
 	struct bt_bap_ep *ep = stream->ep;
+	enum bt_iso_state iso_state;
 	struct net_buf_simple *buf;
 	struct bt_ascs_start_op *req;
 	int err;
@@ -3493,6 +3494,27 @@ int bt_bap_unicast_client_stop(struct bt_bap_stream *stream)
 		return -ENOTCONN;
 	}
 
+	/* ASCS_v1.0 3.2 ASE state machine transitions
+	 *
+	 * If the server detects link loss of a CIS for an ASE in the Streaming state or the
+	 * Disabling state, the server shall immediately transition that ASE to the QoS Configured
+	 * state.
+	 *
+	 * This effectively means that if an ASE no longer has a connected CIS, the server shall
+	 * bring it to the QoS Configured state. That means that we, as a unicast client, should not
+	 * attempt to stop it
+	 */
+	if (ep->iso == NULL) {
+		LOG_DBG("Stream endpoint does not have a CIS, server will stop the ASE");
+		return -EALREADY;
+	}
+
+	iso_state = ep->iso->chan.state;
+	if (iso_state != BT_ISO_STATE_CONNECTED && iso_state != BT_ISO_STATE_CONNECTING) {
+		LOG_DBG("Stream endpoint CIS is not connected, server will stop the ASE");
+		return -EALREADY;
+	}
+
 	buf = bt_bap_unicast_client_ep_create_pdu(stream->conn, BT_ASCS_STOP_OP);
 	if (buf == NULL) {
 		LOG_DBG("Could not create PDU");