Capture TX issues in performance counter instead of spamming console in mavlink app

src/modules/mavlink/mavlink_main.cpp

@@ -192,13 +192,14 @@ mavlink_send_uart_bytes(mavlink_channel_t channel, const uint8_t *ch, int length
 
 			if (buf_free < desired) {
 				/* we don't want to send anything just in half, so return */
+				instance->count_txerr();
 				return;
 			}
 		}
 
 		ssize_t ret = write(uart, ch, desired);
 		if (ret != desired) {
-			warnx("TX FAIL");
+			instance->count_txerr();
 		} else {
 			last_write_success_times[(unsigned)channel] = last_write_try_times[(unsigned)channel];
 		}
@@ -237,7 +238,8 @@ Mavlink::Mavlink() :
 	_flow_control_enabled(true),
 	_message_buffer({}),
 /* performance counters */
-	_loop_perf(perf_alloc(PC_ELAPSED, "mavlink"))
+	_loop_perf(perf_alloc(PC_ELAPSED, "mavlink_el")),
+	_txerr_perf(perf_alloc(PC_COUNT, "mavlink_txe"))
 {
 	_wpm = &_wpm_s;
 	mission.count = 0;
@@ -290,6 +292,7 @@ Mavlink::Mavlink() :
 Mavlink::~Mavlink()
 {
 	perf_free(_loop_perf);
+	perf_free(_txerr_perf);
 
 	if (_task_running) {
 		/* task wakes up every 10ms or so at the longest */
@@ -314,6 +317,12 @@ Mavlink::~Mavlink()
 	LL_DELETE(_mavlink_instances, this);
 }
 
+void
+Mavlink::count_txerr()
+{
+	perf_count(_txerr_perf);
+}
+
 void
 Mavlink::set_mode(enum MAVLINK_MODE mode)
 {
@@ -2169,11 +2178,20 @@ int Mavlink::start_helper(int argc, char *argv[])
 	/* create the instance in task context */
 	Mavlink *instance = new Mavlink();
 
+	int res;
+
+	if (!instance) {
+
+		/* out of memory */
+		res = -ENOMEM;
+		warnx("OUT OF MEM");
+	} else {
 		/* this will actually only return once MAVLink exits */
-	int res = instance->task_main(argc, argv);
+		res = instance->task_main(argc, argv);
 
 		/* delete instance on main thread end */
 		delete instance;
+	}
 
 	return res;
 }

src/modules/mavlink/mavlink_main.h

@@ -213,6 +213,11 @@ public:
 	bool get_wait_to_transmit() { return _wait_to_transmit; }
 	bool should_transmit() { return (!_wait_to_transmit || (_wait_to_transmit && _received_messages)); }
 
+	/**
+	 * Count a transmision error
+	 */
+	void count_txerr();
+
 protected:
 	Mavlink	*next;
 
@@ -282,6 +287,7 @@ private:
 	pthread_mutex_t _message_buffer_mutex;
 
 	perf_counter_t	_loop_perf;			/**< loop performance counter */
+	perf_counter_t	_txerr_perf;			/**< TX error counter */
 
 	/**
 	 * Send one parameter.