rover_pos_control: revert sensor_combined purge

- sensor_combined is only used for scheduling in this module under certain circumstances and should be reviewed and replaced 
 - fixes https://github.com/PX4/Firmware/issues/15628

src/modules/rover_pos_control/RoverPositionControl.cpp

@@ -357,6 +357,7 @@ RoverPositionControl::run()
 	_att_sp_sub = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
 
 	_vehicle_attitude_sub = orb_subscribe(ORB_ID(vehicle_attitude));
+	_sensor_combined_sub = orb_subscribe(ORB_ID(sensor_combined));
 
 	/* rate limit control mode updates to 5Hz */
 	orb_set_interval(_control_mode_sub, 200);
@@ -368,17 +369,19 @@ RoverPositionControl::run()
 	parameters_update(true);
 
 	/* wakeup source(s) */
-	px4_pollfd_struct_t fds[4] {};
+	px4_pollfd_struct_t fds[5];
 
 	/* Setup of loop */
 	fds[0].fd = _global_pos_sub;
 	fds[0].events = POLLIN;
 	fds[1].fd = _manual_control_setpoint_sub;
 	fds[1].events = POLLIN;
-	fds[2].fd = _vehicle_attitude_sub; // Poll attitude
+	fds[2].fd = _sensor_combined_sub;
 	fds[2].events = POLLIN;
-	fds[3].fd = _local_pos_sub; // Added local position as source of position
+	fds[3].fd = _vehicle_attitude_sub; // Poll attitude
 	fds[3].events = POLLIN;
+	fds[4].fd = _local_pos_sub;  // Added local position as source of position
+	fds[4].events = POLLIN;
 
 	while (!should_exit()) {
 
@@ -404,7 +407,7 @@ RoverPositionControl::run()
 		bool manual_mode = _control_mode.flag_control_manual_enabled;
 
 		/* only run controller if position changed */
-		if (fds[0].revents & POLLIN || fds[3].revents & POLLIN) {
+		if (fds[0].revents & POLLIN || fds[4].revents & POLLIN) {
 			perf_begin(_loop_perf);
 
 			/* load local copies */
@@ -473,7 +476,7 @@ RoverPositionControl::run()
 			perf_end(_loop_perf);
 		}
 
-		if (fds[2].revents & POLLIN) {
+		if (fds[3].revents & POLLIN) {
 
 			vehicle_attitude_poll();
 
@@ -502,6 +505,24 @@ RoverPositionControl::run()
 				_act_controls.control[actuator_controls_s::INDEX_THROTTLE] = _manual_control_setpoint.z;
 			}
 		}
+
+		if (fds[2].revents & POLLIN) {
+
+			orb_copy(ORB_ID(sensor_combined), _sensor_combined_sub, &_sensor_combined);
+
+			//orb_copy(ORB_ID(vehicle_attitude), _vehicle_attitude_sub, &_vehicle_att);
+			_act_controls.timestamp = hrt_absolute_time();
+
+			/* Only publish if any of the proper modes are enabled */
+			if (_control_mode.flag_control_velocity_enabled ||
+			    _control_mode.flag_control_attitude_enabled ||
+			    _control_mode.flag_control_position_enabled ||
+			    manual_mode) {
+				/* publish the actuator controls */
+				_actuator_controls_pub.publish(_act_controls);
+			}
+		}
+
 	}
 
 	orb_unsubscribe(_control_mode_sub);
@@ -510,6 +531,9 @@ RoverPositionControl::run()
 	orb_unsubscribe(_manual_control_setpoint_sub);
 	orb_unsubscribe(_pos_sp_triplet_sub);
 	orb_unsubscribe(_vehicle_attitude_sub);
+	orb_unsubscribe(_sensor_combined_sub);
+
+	warnx("exiting.\n");
 }
 
 int RoverPositionControl::task_spawn(int argc, char *argv[])

src/modules/rover_pos_control/RoverPositionControl.hpp

@@ -61,6 +61,7 @@
 #include <uORB/topics/parameter_update.h>
 #include <uORB/topics/position_controller_status.h>
 #include <uORB/topics/position_setpoint_triplet.h>
+#include <uORB/topics/sensor_combined.h>
 #include <uORB/topics/vehicle_acceleration.h>
 #include <uORB/topics/vehicle_attitude.h>
 #include <uORB/topics/vehicle_attitude_setpoint.h>
@@ -109,6 +110,7 @@ private:
 	int		_pos_sp_triplet_sub{-1};
 	int		_att_sp_sub{-1};
 	int		_vehicle_attitude_sub{-1};
+	int		_sensor_combined_sub{-1};
 
 	uORB::Subscription	_parameter_update_sub{ORB_ID(parameter_update)};
 
@@ -120,6 +122,7 @@ private:
 	vehicle_local_position_s		_local_pos{};			/**< global vehicle position */
 	actuator_controls_s				_act_controls{};		/**< direct control of actuators */
 	vehicle_attitude_s				_vehicle_att{};
+	sensor_combined_s				_sensor_combined{};
 
 	SubscriptionData<vehicle_acceleration_s>		_vehicle_acceleration_sub{ORB_ID(vehicle_acceleration)};