fix AudioUnit parameter listening to work with new ParameterChangedExternally semantics

diff --git a/libs/ardour/audio_unit.cc b/libs/ardour/audio_unit.cc
index 045669b29bcb25a540e0604a1ed3fb7cd406a286..e8f7e0a1edfffb0de95d85b5063626c209d642ec 100644 (file)
--- a/libs/ardour/audio_unit.cc
+++ b/libs/ardour/audio_unit.cc
@@ -924,7 +924,8 @@ AUPlugin::set_parameter (uint32_t which, float val)
        theEvent.mArgument.mParameter.mElement = d.element;
 
        DEBUG_TRACE (DEBUG::AudioUnits, "notify about parameter change\n");
-       AUEventListenerNotify (NULL, this, &theEvent);
+        /* Note the 1st argument, which means "Don't notify us about a change we made ourselves" */
+        AUEventListenerNotify (_parameter_listener, NULL, &theEvent);
 
        Plugin::set_parameter (which, val);
 }
@@ -3094,12 +3095,10 @@ AUPlugin::parameter_change_listener (void* /*arg*/, void* src, const AudioUnitEv
                 EndTouch (i->second);
                 break;
         case kAudioUnitEvent_ParameterValueChange:
-               if (src != this) {
-                       std::cerr << "something changed " << i->second << " to " << new_value << std::endl;
-                       ParameterChangedExternally (i->second, new_value);
-               } else {
-                       std::cerr << "plugin changed " << i->second << " ignore it\n";
-               }
+                /* whenever we change a parameter, we request that we are NOT notified of the change, so anytime we arrive here, it
+                   means that something else (i.e. the plugin GUI) made the change.
+                */
+                ParameterChangedExternally (i->second, new_value);
                 break;
         default:
                 break;