logger: use ORB_ID enum as msg_id

src/modules/logger/logger.cpp

@@ -720,7 +720,7 @@ void Logger::run()
 					// each message consists of a header followed by an orb data object
 					const size_t msg_size = sizeof(ulog_message_data_header_s) + sub.get_topic()->o_size_no_padding;
 					const uint16_t write_msg_size = static_cast<uint16_t>(msg_size - ULOG_MSG_HEADER_LEN);
-					const uint16_t write_msg_id = sub.msg_id;
+					const uint16_t write_msg_id = static_cast<uint16_t>(sub.get_orb_id());
 
 					//write one byte after another (necessary because of alignment)
 					_msg_buffer[0] = (uint8_t)write_msg_size;
@@ -1605,18 +1605,7 @@ void Logger::write_all_add_logged_msg(LogType type)
 void Logger::write_add_logged_msg(LogType type, LoggerSubscription &subscription)
 {
 	ulog_message_add_logged_s msg;
-
+	msg.msg_id = static_cast<uint16_t>(subscription.get_orb_id());
-	if (subscription.msg_id == MSG_ID_INVALID) {
-		if (_next_topic_id == MSG_ID_INVALID) {
-			// if we land here an uint8 is too small -> switch to uint16
-			PX4_ERR("limit for _next_topic_id reached");
-			return;
-		}
-
-		subscription.msg_id = _next_topic_id++;
-	}
-
-	msg.msg_id = subscription.msg_id;
 	msg.multi_id = subscription.get_instance();
 
 	int message_name_len = strlen(subscription.get_topic()->o_name);

src/modules/logger/logger.h

@@ -75,8 +75,6 @@ struct LoggerSubscription : public uORB::SubscriptionInterval {
 	LoggerSubscription(ORB_ID id, uint32_t interval_ms = 0, uint8_t instance = 0) :
 		uORB::SubscriptionInterval(id, interval_ms * 1000, instance)
 	{}
-
-	uint8_t msg_id{MSG_ID_INVALID};
 };
 
 class Logger : public ModuleBase<Logger>, public ModuleParams
@@ -335,7 +333,6 @@ private:
 	uint32_t					_log_interval{0};
 	const orb_metadata				*_polling_topic_meta{nullptr}; ///< if non-null, poll on this topic instead of sleeping
 	orb_advert_t					_mavlink_log_pub{nullptr};
-	uint8_t						_next_topic_id{0}; ///< id of next subscribed ulog topic
 	char						*_replay_file_name{nullptr};
 	bool						_should_stop_file_log{false}; /**< if true _next_load_print is set and file logging
 											will be stopped after load printing (for the full log) */

src/modules/uORB/Subscription.hpp

@@ -159,6 +159,7 @@ public:
 
 	uint8_t  get_instance() const { return _instance; }
 	unsigned get_last_generation() const { return _last_generation; }
+	ORB_ID get_orb_id() const { return _orb_id; }
 	orb_id_t get_topic() const { return get_orb_meta(_orb_id); }
 
 protected:

src/modules/uORB/SubscriptionInterval.hpp

@@ -138,6 +138,7 @@ public:
 	uint8_t		get_instance() const { return _subscription.get_instance(); }
 	uint32_t        get_interval_us() const { return _interval_us; }
 	unsigned	get_last_generation() const { return _subscription.get_last_generation(); }
+	ORB_ID          get_orb_id() const { return _subscription.get_orb_id(); }
 	orb_id_t	get_topic() const { return _subscription.get_topic(); }
 
 	/**