avdtp: limit l2cap mtu to largest br/edr packet

CHANGELOG.md

@@ -23,6 +23,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - HFP AG: fix setup of audio connection in service level established event
 - HFP AG: fix BCM WBS setup
 - HID Device: set Report Mode as default
+- AVDTP: limit L2CAP MTU to largest BR/EDR packet, fixes A2DP Sink role for some Samsung TV
 - AVRCP: reject incoming second l2cap connection
 - AVRCP: generate command for avrcp_controller_get_element_attributes dynamically
 - GATT Client: ignore notifications/indications until re-encrypted for bonded device without ENABLE_LE_PROACTIVE_AUTHENTICATION

src/classic/avdtp.c

@@ -688,7 +688,7 @@ static void avdtp_handle_sdp_query_succeeded(avdtp_connection_t * connection){
             break;
         default:
             connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
-            l2cap_create_channel(avdtp_packet_handler, connection->remote_addr, connection->avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
+            l2cap_create_channel(avdtp_packet_handler, connection->remote_addr, connection->avdtp_l2cap_psm, AVDTP_L2CAP_MTU, NULL);
             break;
     }
 }
@@ -1621,7 +1621,7 @@ uint8_t is_avdtp_remote_seid_registered(avdtp_stream_endpoint_t * stream_endpoin
 void avdtp_init(void){
     if (!avdtp_l2cap_registered){
         avdtp_l2cap_registered = true;
-        l2cap_register_service(&avdtp_packet_handler, BLUETOOTH_PSM_AVDTP, 0xffff, gap_get_security_level());
+        l2cap_register_service(&avdtp_packet_handler, BLUETOOTH_PSM_AVDTP, AVDTP_L2CAP_MTU, gap_get_security_level());
     }
 }
 

src/classic/avdtp.h

@@ -56,6 +56,9 @@
 extern "C" {
 #endif
 
+// Limit L2CAP MTU to fit largest packet for BR/EDR
+#define AVDTP_L2CAP_MTU (HCI_ACL_3DH5_SIZE - L2CAP_HEADER_SIZE)
+
 #define AVDTP_MAX_NUM_SEPS 10
 #define AVDTP_MAX_CSRC_NUM 15
 #define AVDTP_MAX_CONTENT_PROTECTION_TYPE_VALUE_LEN 10