Fix reduced channelcount when restarting engine with different device

1. Start engine with a stereo soundcard (n_inputs was set to 2)
2. Restart engine with multi-channel soundcard, n_inputs remained a 2)

libs/backends/alsa/alsa_audiobackend.cc

@@ -71,8 +71,6 @@ AlsaAudioBackend::AlsaAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _samplerate (48000)
 	, _samples_per_period (1024)
 	, _periods_per_cycle (2)
-	, _n_inputs (0)
-	, _n_outputs (0)
 	, _systemic_audio_input_latency (0)
 	, _systemic_audio_output_latency (0)
 	, _midi_device_thread_active (false)
@@ -919,24 +917,6 @@ AlsaAudioBackend::_start (bool for_latency_measurement)
 	}
 #endif
 
-	if (_n_outputs != _pcmi->nplay ()) {
-		if (_n_outputs == 0) {
-			_n_outputs = _pcmi->nplay ();
-		} else {
-			_n_outputs = std::min (_n_outputs, _pcmi->nplay ());
-		}
-		PBD::info << _("AlsaAudioBackend: adjusted output channel count to match device.") << endmsg;
-	}
-
-	if (_n_inputs != _pcmi->ncapt ()) {
-		if (_n_inputs == 0) {
-			_n_inputs = _pcmi->ncapt ();
-		} else {
-			_n_inputs = std::min (_n_inputs, _pcmi->ncapt ());
-		}
-		PBD::info << _("AlsaAudioBackend: adjusted input channel count to match device.") << endmsg;
-	}
-
 	if (_pcmi->fsize () != _samples_per_period) {
 		_samples_per_period = _pcmi->fsize ();
 		PBD::warning << string_compose (_("AlsaAudioBackend: samples per period does not match, using %1."), _samples_per_period) << endmsg;
@@ -1246,8 +1226,8 @@ AlsaAudioBackend::register_system_audio_ports ()
 {
 	LatencyRange lr;
 
-	const int a_ins = _n_inputs;
-	const int a_out = _n_outputs;
+	const int a_ins = _pcmi->ncapt ();
+	const int a_out = _pcmi->nplay ();
 
 	const uint32_t lcpp = (_periods_per_cycle - 2) * _samples_per_period;
 

libs/backends/alsa/alsa_audiobackend.h

@@ -302,9 +302,6 @@ class AlsaAudioBackend : public AudioBackend, public PortEngineSharedImpl
 		size_t _periods_per_cycle;
 		static size_t _max_buffer_size;
 
-		uint32_t _n_inputs;
-		uint32_t _n_outputs;
-
 		uint32_t _systemic_audio_input_latency;
 		uint32_t _systemic_audio_output_latency;
 

libs/backends/coreaudio/coreaudio_backend.cc

@@ -108,8 +108,6 @@ CoreAudioBackend::CoreAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _midi_driver_option(_("CoreMidi"))
 	, _samplerate (48000)
 	, _samples_per_period (1024)
-	, _n_inputs (0)
-	, _n_outputs (0)
 	, _systemic_audio_input_latency (0)
 	, _systemic_audio_output_latency (0)
 	, _hw_audio_input_latency (0)
@@ -564,24 +562,6 @@ CoreAudioBackend::_start (bool for_latency_measurement)
 		return error_code;
 	}
 
-	if (_n_outputs != _pcmio->n_playback_channels ()) {
-		if (_n_outputs == 0) {
-			_n_outputs = _pcmio->n_playback_channels ();
-		} else {
-			_n_outputs = std::min (_n_outputs, _pcmio->n_playback_channels ());
-		}
-		PBD::info << _("CoreAudioBackend: adjusted output channel count to match device.") << endmsg;
-	}
-
-	if (_n_inputs != _pcmio->n_capture_channels ()) {
-		if (_n_inputs == 0) {
-			_n_inputs = _pcmio->n_capture_channels ();
-		} else {
-			_n_inputs = std::min (_n_inputs, _pcmio->n_capture_channels ());
-		}
-		PBD::info << _("CoreAudioBackend: adjusted input channel count to match device.") << endmsg;
-	}
-
 	if (_pcmio->sample_rate() != _samplerate) {
 		_samplerate = _pcmio->sample_rate();
 		engine.sample_rate_change (_samplerate);
@@ -927,8 +907,8 @@ CoreAudioBackend::register_system_audio_ports()
 {
 	LatencyRange lr;
 
-	const uint32_t a_ins = _n_inputs;
-	const uint32_t a_out = _n_outputs;
+	const uint32_t a_ins = _pcmio->n_capture_channels ();
+	const uint32_t a_out = _pcmio->n_playback_channels ();
 
 	const uint32_t coreaudio_reported_input_latency = _pcmio->get_latency(name_to_id(_input_audio_device, Input), true);
 	const uint32_t coreaudio_reported_output_latency = _pcmio->get_latency(name_to_id(_output_audio_device, Output), false);

libs/backends/coreaudio/coreaudio_backend.h

@@ -353,9 +353,6 @@ class CoreAudioBackend : public AudioBackend, public PortEngineSharedImpl {
 	size_t _samples_per_period;
 	static size_t _max_buffer_size;
 
-	uint32_t _n_inputs;
-	uint32_t _n_outputs;
-
 	uint32_t _systemic_audio_input_latency;
 	uint32_t _systemic_audio_output_latency;
 

libs/backends/portaudio/portaudio_backend.cc

@@ -84,8 +84,6 @@ PortAudioBackend::PortAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _midi_driver_option(winmme_driver_name)
 	, _samplerate (48000)
 	, _samples_per_period (1024)
-	, _n_inputs (0)
-	, _n_outputs (0)
 	, _systemic_audio_input_latency (0)
 	, _systemic_audio_output_latency (0)
 	, _dsp_load (0)
@@ -612,15 +610,6 @@ PortAudioBackend::_start (bool for_latency_measurement)
 		return AudioDeviceOpenError;
 	}
 
-	if (_n_outputs != _pcmio->n_playback_channels ()) {
-		_n_outputs = _pcmio->n_playback_channels ();
-		PBD::info << get_error_string(OutputChannelCountNotSupportedError) << endmsg;
-	}
-
-	if (_n_inputs != _pcmio->n_capture_channels ()) {
-		_n_inputs = _pcmio->n_capture_channels ();
-		PBD::info << get_error_string(InputChannelCountNotSupportedError) << endmsg;
-	}
 #if 0
 	if (_pcmio->samples_per_period() != _samples_per_period) {
 		_samples_per_period = _pcmio->samples_per_period();
@@ -1196,8 +1185,8 @@ PortAudioBackend::register_system_audio_ports()
 {
 	LatencyRange lr;
 
-	const uint32_t a_ins = _n_inputs;
-	const uint32_t a_out = _n_outputs;
+	const uint32_t a_ins = _pcmio->n_capture_channels ();
+	const uint32_t a_out = _pcmio->n_playback_channels ();
 
 	/* audio ports */
 	lr.min = lr.max = (_measure_latency ? 0 : _systemic_audio_input_latency);

libs/backends/portaudio/portaudio_backend.h

@@ -322,9 +322,6 @@ class PortAudioBackend : public AudioBackend, public PortEngineSharedImpl {
 		size_t _samples_per_period;
 		static size_t _max_buffer_size;
 
-		uint32_t _n_inputs;
-		uint32_t _n_outputs;
-
 		uint32_t _systemic_audio_input_latency;
 		uint32_t _systemic_audio_output_latency;