Avoid RC processing when no new RC data was received.

src/main/fc/fc_core.c

@@ -392,13 +392,13 @@ static bool canUpdateVTX(void)
 /*
  * processRx called from taskUpdateRxMain
  */
-void processRx(timeUs_t currentTimeUs)
+bool processRx(timeUs_t currentTimeUs)
 {
     static bool armedBeeperOn = false;
     static bool airmodeIsActivated;
 
     if (!calculateRxChannelsAndUpdateFailsafe(currentTimeUs)) {
-        return;
+        return false;
     }
 
     // in 3D mode, we need to be able to disarm by switch at any time
@@ -600,6 +600,8 @@ void processRx(timeUs_t currentTimeUs)
         handleVTXControlButton();
     }
 #endif
+
+    return true;
 }
 
 static void subTaskPidController(timeUs_t currentTimeUs)

src/main/fc/fc_core.h

@@ -42,7 +42,7 @@ void resetArmingDisabled(void);
 void disarm(void);
 void tryArm(void);
 
-void processRx(timeUs_t currentTimeUs);
+bool processRx(timeUs_t currentTimeUs);
 void updateArmingStatus(void);
 void updateRcCommands(void);
 

src/main/fc/fc_tasks.c

@@ -132,7 +132,10 @@ static void taskUpdateAccelerometer(timeUs_t currentTimeUs)
 
 static void taskUpdateRxMain(timeUs_t currentTimeUs)
 {
-    processRx(currentTimeUs);
+    if (!processRx(currentTimeUs)) {
+        return;
+    }
+
     isRXDataNew = true;
 
 #if !defined(USE_ALT_HOLD)