AP_RCTelemetry: don't process VTX frames when VTX support is disabled

libraries/AP_RCTelemetry/AP_CRSF_Telem.cpp

@@ -392,7 +392,12 @@ void AP_CRSF_Telem::process_vtx_frame(VTXFrame* vtx) {
         vtx->is_in_pitmode, vtx->power, vtx->pitmode);
     AP_VideoTX& apvtx = AP::vtx();
 
-    apvtx.set_enabled(vtx->is_vtx_available);
+    // the user may have a VTX connected but not want AP to control it
+    // (for instance because they are using myVTX on the transmitter)
+    if (!apvtx.get_enabled()) {
+        return;
+    }
+
     apvtx.set_band(vtx->band);
     apvtx.set_channel(vtx->channel);
     if (vtx->is_in_user_frequency_mode) {
@@ -428,12 +433,17 @@ void AP_CRSF_Telem::process_vtx_frame(VTXFrame* vtx) {
     _vtx_power_change_pending = _vtx_freq_change_pending = _vtx_options_change_pending = false;
 }
 
-void AP_CRSF_Telem::process_vtx_telem_frame(VTXTelemetryFrame* vtx) {
+void AP_CRSF_Telem::process_vtx_telem_frame(VTXTelemetryFrame* vtx)
+{
     vtx->frequency = be16toh(vtx->frequency);
     debug("VTXTelemetry: Freq: %d, PitMode: %d, Power: %d", vtx->frequency, vtx->pitmode, vtx->power);
 
     AP_VideoTX& apvtx = AP::vtx();
 
+    if (!apvtx.get_enabled()) {
+        return;
+    }
+
     apvtx.set_frequency_mhz(vtx->frequency);
 
     AP_VideoTX::VideoBand band;
@@ -550,6 +560,10 @@ void AP_CRSF_Telem::update_vtx_params()
 {
     AP_VideoTX& vtx = AP::vtx();
 
+    if (!vtx.get_enabled()) {
+        return;
+    }
+
     _vtx_freq_change_pending = vtx.update_band() || vtx.update_channel() || vtx.update_frequency() || _vtx_freq_change_pending;
     _vtx_power_change_pending = vtx.update_power() || _vtx_power_change_pending;
     _vtx_options_change_pending = vtx.update_options() || _vtx_options_change_pending;