sensors app: Comment handling of old param values properly

1 files changed, 17 insertions, 10 deletions

diff --git a/src/modules/sensors/sensors.cpp b/src/modules/sensors/sensors.cpp
index 666025c71..9a90c84e0 100644
--- a/src/modules/sensors/sensors.cpp
+++ b/src/modules/sensors/sensors.cpp
@@ -1519,16 +1519,23 @@ Sensors::parameter_update_poll(bool forced)
 						int32_t mag_rot = 0;
 						param_get(param_find(str), &mag_rot);
 
-						/* handling of old setups, will be removed */
-						if (s == 0) {
-							int32_t deprecated_mag_rot = 0;
-							param_get(param_find("SENS_EXT_MAG_ROT"), &deprecated_mag_rot);
-
-							/* if the old param is non-zero, set the new one to the same value */
-							if ((deprecated_mag_rot != 0) && (mag_rot <= 0)) {
-								mag_rot = deprecated_mag_rot;
-								param_set_no_notification(param_find(str), &mag_rot);
-							}
+						/* handling of old setups, will be removed later (noted Feb 2015) */
+						int32_t deprecated_mag_rot = 0;
+						param_get(param_find("SENS_EXT_MAG_ROT"), &deprecated_mag_rot);
+
+						/*
+						 * If the deprecated parameter is non-default (is != 0),
+						 * and the new parameter is default (is == 0), then this board
+						 * was configured already and we need to copy the old value
+						 * to the new parameter.
+						 * The < 0 case is special: It means that this param slot was
+						 * used previously by an internal sensor, but the the call above
+						 * proved that it is currently occupied by an external sensor.
+						 * In that case we consider the orientation to be default as well.
+						 */
+						if ((deprecated_mag_rot != 0) && (mag_rot <= 0)) {
+							mag_rot = deprecated_mag_rot;
+							param_set_no_notification(param_find(str), &mag_rot);
 						}
 
 						/* handling of transition from internal to external */