From ce552a33647daf83a21c2fd7313df7b3589e84b5 Mon Sep 17 00:00:00 2001
From: Daniel Agar <daniel@agar.ca>
Date: Fri, 12 Feb 2021 16:29:26 -0500
Subject: [PATCH] navigator: RTL don't get invalid params

---
 src/modules/navigator/rtl.cpp | 16 ++++++++--------
 src/modules/navigator/rtl.h   |  5 +++--
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/modules/navigator/rtl.cpp b/src/modules/navigator/rtl.cpp
index 0ebddbe77e..62b339a627 100644
--- a/src/modules/navigator/rtl.cpp
+++ b/src/modules/navigator/rtl.cpp
@@ -642,27 +642,27 @@ void RTL::get_rtl_xy_z_speed(float &xy, float &z)
 
 		switch (vehicle_type) {
 		case vehicle_status_s::VEHICLE_TYPE_ROTARY_WING:
-			_rtl_xy_speed = param_find("MPC_XY_CRUISE");
-			_rtl_descent_speed = param_find("MPC_Z_VEL_MAX_DN");
+			_param_rtl_xy_speed = param_find("MPC_XY_CRUISE");
+			_param_rtl_descent_speed = param_find("MPC_Z_VEL_MAX_DN");
 			break;
 
 		case vehicle_status_s::VEHICLE_TYPE_FIXED_WING:
-			_rtl_xy_speed = param_find("FW_AIRSPD_TRIM");
-			_rtl_descent_speed = param_find("FW_T_SINK_MIN");
+			_param_rtl_xy_speed = param_find("FW_AIRSPD_TRIM");
+			_param_rtl_descent_speed = param_find("FW_T_SINK_MIN");
 			break;
 
 		case vehicle_status_s::VEHICLE_TYPE_ROVER:
-			_rtl_xy_speed = param_find("GND_SPEED_THR_SC");
-			_rtl_descent_speed = 65535;
+			_param_rtl_xy_speed = param_find("GND_SPEED_THR_SC");
+			_param_rtl_descent_speed = PARAM_INVALID;
 			break;
 		}
 	}
 
-	if (param_get(_rtl_xy_speed, &xy) != 0) {
+	if ((_param_rtl_xy_speed == PARAM_INVALID) || param_get(_param_rtl_xy_speed, &xy) != PX4_OK) {
 		xy = 1e6f;
 	}
 
-	if (param_get(_rtl_descent_speed, &z) != 0) {
+	if ((_param_rtl_descent_speed == PARAM_INVALID) || param_get(_param_rtl_descent_speed, &z) != PX4_OK) {
 		z = 1e6f;
 	}
 
diff --git a/src/modules/navigator/rtl.h b/src/modules/navigator/rtl.h
index 57cd49b2da..6b5cd4118d 100644
--- a/src/modules/navigator/rtl.h
+++ b/src/modules/navigator/rtl.h
@@ -165,8 +165,9 @@ private:
 	// These need to point at different parameters depending on vehicle type.
 	// Can't hard-code them because we have non-MC/FW/Rover builds
 	uint8_t _rtl_vehicle_type{vehicle_status_s::VEHICLE_TYPE_UNKNOWN};
-	param_t _rtl_xy_speed{PARAM_INVALID};
-	param_t _rtl_descent_speed{PARAM_INVALID};
+
+	param_t _param_rtl_xy_speed{PARAM_INVALID};
+	param_t _param_rtl_descent_speed{PARAM_INVALID};
 
 	uORB::SubscriptionData<wind_estimate_s>		_wind_estimate_sub{ORB_ID(wind_estimate)};
 	uORB::Publication<rtl_flight_time_s>		_rtl_flight_time_pub{ORB_ID(rtl_flight_time)};