We tried to write a 64k data to rfcomm socket, but it will break before sending all of the data out. The problem is in function rfcomm_sock_sendmsg() in net/bluetooth/rfcomm/sock.c, it breaks after calling sock_alloc_send_skb(). static int rfcomm_sock_sendmsg(...) { ... skb = sock_alloc_send_skb(sk, size + RFCOMM_SKB_RESERVE, msg->msg_flags & MSG_DONTWAIT, &err); if (!skb) break; ... } Looks the send buffer is not adequate. Then I increased the send buffer size in function rfcomm_sock_alloc(), build kernel and try again, this time the sendmsg can complete sending all the data. Can we use the setsockopt() method to change the socket's send/receive buffer size, just like the usual tcp/ip socket? Thanks, Zhu Lan -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html