From a8ff35accb500da06d114335ee03ac67bcd26863 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 30 Mar 2020 16:58:55 +0200
Subject: [PATCH] Reset DSP load on backend re-start and after freewheeling

---
 libs/backends/alsa/alsa_audiobackend.cc        | 2 ++
 libs/backends/coreaudio/coreaudio_backend.cc   | 2 ++
 libs/backends/portaudio/portaudio_backend.cc   | 7 +++++++
 libs/backends/pulseaudio/pulseaudio_backend.cc | 2 ++
 4 files changed, 13 insertions(+)

diff --git a/libs/backends/alsa/alsa_audiobackend.cc b/libs/backends/alsa/alsa_audiobackend.cc
index 947b6d5992..ae4ef51448 100644
--- a/libs/backends/alsa/alsa_audiobackend.cc
+++ b/libs/backends/alsa/alsa_audiobackend.cc
@@ -2107,6 +2107,7 @@ AlsaAudioBackend::main_process_thread ()
 		Glib::usleep (1000000 * (_samples_per_period / _samplerate ));
 	}
 
+	_dsp_load_calc.reset ();
 	_pcmi->pcm_start ();
 
 	while (_run) {
@@ -2124,6 +2125,7 @@ AlsaAudioBackend::main_process_thread ()
 				_pcmi->pcm_stop ();
 				_pcmi->pcm_start ();
 				drain_slaves = true;
+				_dsp_load_calc.reset ();
 			}
 		}
 
diff --git a/libs/backends/coreaudio/coreaudio_backend.cc b/libs/backends/coreaudio/coreaudio_backend.cc
index 3e99155bda..13d739ebf6 100644
--- a/libs/backends/coreaudio/coreaudio_backend.cc
+++ b/libs/backends/coreaudio/coreaudio_backend.cc
@@ -708,6 +708,7 @@ CoreAudioBackend::_start (bool for_latency_measurement)
 	_port_change_flag = true;
 	pre_process ();
 
+	_dsp_load_calc.reset ();
 	// all systems go.
 	_pcmio->set_xrun_callback (xrun_callback_ptr, this);
 	_preinit = false;
@@ -1797,6 +1798,7 @@ CoreAudioBackend::process_callback (const uint32_t n_samples, const uint64_t hos
 	if (!_run || _freewheel || _preinit) {
 		// NB if we return 1, the output is
 		// zeroed by the coreaudio callback
+		_dsp_load_calc.reset ();
 		return 1;
 	}
 
diff --git a/libs/backends/portaudio/portaudio_backend.cc b/libs/backends/portaudio/portaudio_backend.cc
index db57b3cc31..71f50b39ba 100644
--- a/libs/backends/portaudio/portaudio_backend.cc
+++ b/libs/backends/portaudio/portaudio_backend.cc
@@ -684,6 +684,8 @@ PortAudioBackend::_start (bool for_latency_measurement)
 	engine.reconnect_ports ();
 	_port_change_flag = false;
 
+	_dsp_calc.reset ();
+
 	if (_use_blocking_api) {
 		if (!start_blocking_process_thread()) {
 			return ProcessThreadStartError;
@@ -925,6 +927,7 @@ PortAudioBackend::freewheel_process_thread()
 				_freewheel_ack = false; // prepare next handshake
 				_midiio->set_enabled(true);
 				engine.freewheel_callback (_freewheeling);
+				_dsp_calc.reset ();
 			} else {
 				first_run = true;
 				_freewheel = true;
@@ -1883,11 +1886,15 @@ PortAudioBackend::blocking_process_thread ()
 	DWORD tid = GetCurrentThreadId ();
 	DEBUG_THREADS (string_compose ("Process Thread Master ID: %1\n", tid));
 
+	_dsp_calc.reset ();
 	while (_run) {
 
 		if (_freewheeling != _freewheel) {
 			_freewheel = _freewheeling;
 			engine.freewheel_callback (_freewheel);
+			if (!_freewheel) {
+				_dsp_calc.reset ();
+			}
 		}
 
 		if (!_freewheel) {
diff --git a/libs/backends/pulseaudio/pulseaudio_backend.cc b/libs/backends/pulseaudio/pulseaudio_backend.cc
index b742a86c86..9d550a3449 100644
--- a/libs/backends/pulseaudio/pulseaudio_backend.cc
+++ b/libs/backends/pulseaudio/pulseaudio_backend.cc
@@ -1412,6 +1412,7 @@ PulseAudioBackend::main_process_thread ()
 		}
 	}
 
+	_dsp_load_calc.reset ();
 	stream_latency_update_cb (p_stream, this);
 
 	while (_run) {
@@ -1436,6 +1437,7 @@ PulseAudioBackend::main_process_thread ()
 				if (!sync_pulse (pa_stream_flush (p_stream, stream_operation_cb, this)) || !_operation_succeeded) {
 					break;
 				}
+				_dsp_load_calc.reset ();
 			}
 		}