improve AU Latency PropertyChange Events

diff --git a/libs/ardour/ardour/audio_unit.h b/libs/ardour/ardour/audio_unit.h
index 24f427b1247ac4144b71b8badf513b2238f278ee..c5c5ed4a95a466ab93d800b86e1b17f15aa2fd5e 100644 (file)
--- a/libs/ardour/ardour/audio_unit.h
+++ b/libs/ardour/ardour/audio_unit.h
@@ -171,7 +171,7 @@ class LIBARDOUR_API AUPlugin : public ARDOUR::Plugin
        int32_t output_channels;
        std::vector<std::pair<int,int> > io_configs;
        framecnt_t _last_nframes;
-       mutable framecnt_t _current_latency;
+       mutable volatile guint _current_latency;
        bool _requires_fixed_size_buffers;
        AudioBufferList* buffers;
        bool _has_midi_input;

diff --git a/libs/ardour/audio_unit.cc b/libs/ardour/audio_unit.cc
index 3e6bdfb69118f8fbaa3eb29b21aa1cfa7e3f9486..85a387e9339aa6b9b7e0d6fe9393fd3b2da92730 100644 (file)
--- a/libs/ardour/audio_unit.cc
+++ b/libs/ardour/audio_unit.cc
@@ -431,7 +431,7 @@ AUPlugin::AUPlugin (AudioEngine& engine, Session& session, boost::shared_ptr<CAC
        , unit (new CAAudioUnit)
        , initialized (false)
        , _last_nframes (0)
-       , _current_latency (-1)
+       , _current_latency (UINT_MAX)
        , _requires_fixed_size_buffers (false)
        , buffers (0)
        , variable_inputs (false)
@@ -472,7 +472,7 @@ AUPlugin::AUPlugin (const AUPlugin& other)
        , unit (new CAAudioUnit)
        , initialized (false)
        , _last_nframes (0)
-       , _current_latency (-1)
+       , _current_latency (UINT_MAX)
        , _requires_fixed_size_buffers (false)
        , buffers (0)
        , variable_inputs (false)
@@ -955,10 +955,12 @@ AUPlugin::default_value (uint32_t port)
 framecnt_t
 AUPlugin::signal_latency () const
 {
-       if (_current_latency < 0) {
-               _current_latency = unit->Latency() * _session.frame_rate();
+       guint lat = g_atomic_int_get (&_current_latency);;
+       if (lat == UINT_MAX) {
+               lat = unit->Latency() * _session.frame_rate();
+               g_atomic_int_set (&_current_latency, lat);
        }
-       return _current_latency;
+       return lat;
 }
 
 void
@@ -3474,9 +3476,9 @@ AUPlugin::parameter_change_listener (void* /*arg*/, void* src, const AudioUnitEv
 {
        if (event->mEventType == kAudioUnitEvent_PropertyChange) {
                if (event->mArgument.mProperty.mPropertyID == kAudioUnitProperty_Latency) {
-                       DEBUG_TRACE (DEBUG::AudioUnits, string_compose("AU Latency Change Event %1 <> %1\n", new_value, unit->Latency()));
-                       // TODO atomically set //_current_latency = -1;
-                       _current_latency = unit->Latency() * _session.frame_rate(); // TODO: check: new_value
+                       DEBUG_TRACE (DEBUG::AudioUnits, string_compose("AU Latency Change Event %1 <> %2\n", new_value, unit->Latency()));
+                       guint lat = unit->Latency() * _session.frame_rate();
+                       g_atomic_int_set (&_current_latency, lat);
                }
                return;
        }