fix AudioOut pacing

Co-authored-by: Stefanos Costa <stefanos.costa1999@gmail.com>

src/libs/audio.cpp

@@ -82,6 +82,7 @@ public:
 	Id       AudioOutOpen(int type, uint32_t samples_num, uint32_t freq, Format format);
 	bool     AudioOutClose(Id handle);
 	bool     AudioOutValid(Id handle);
+	bool     AudioOutHasDevice(Id handle);
 	bool     AudioOutSetVolume(Id handle, uint32_t bitflag, const int* volume);
 	uint32_t AudioOutOutputs(OutputParam* params, uint32_t num, bool blocking = true);
 	bool     AudioOutGetStatus(Id handle, int* type, int* channels_num);
@@ -152,6 +153,10 @@ void AudioOutClose(int handle) {
 	}
 }
 
+bool AudioOutHasDevice(int handle) {
+	return g_audio != nullptr && handle > 0 && g_audio->AudioOutHasDevice(Audio::Id(handle));
+}
+
 uint32_t AudioOutOutputs(const OutputParam* params, uint32_t num, bool blocking) {
 	if (g_audio == nullptr || params == nullptr || num == 0) {
 		return 0;
@@ -451,6 +456,13 @@ bool Audio::AudioOutValid(Id handle) {
 	        m_out_ports[handle.GetId()].used);
 }
 
+bool Audio::AudioOutHasDevice(Id handle) {
+	Common::LockGuard lock(m_mutex);
+
+	return (handle.GetId() >= 0 && handle.GetId() < OUT_PORTS_MAX &&
+	        m_out_ports[handle.GetId()].used && m_out_ports[handle.GetId()].audio_device != 0);
+}
+
 bool Audio::AudioOutGetStatus(Id handle, int* type, int* channels_num) {
 	Common::LockGuard lock(m_mutex);
 
@@ -516,16 +528,18 @@ uint32_t Audio::AudioOutOutputs(OutputParam* params, uint32_t num, bool blocking
 		max_wait_time      = (wait_time > max_wait_time ? wait_time : max_wait_time);
 	}
 
-	bool all_ports_have_device = true;
+	bool any_port_has_device = false;
 	for (uint32_t i = 0; i < num; i++) {
-		if (m_out_ports[params[i].handle.GetId()].audio_device == 0) {
+		if (m_out_ports[params[i].handle.GetId()].audio_device != 0) {
-			all_ports_have_device = false;
+			any_port_has_device = true;
 			break;
 		}
 	}
 
-	// Device-backed ports are paced by the SDL queue above.
+	// One real output device is enough to pace the whole synchronized batch. Applying the fallback
-	if (blocking && max_wait_time != 0 && !all_ports_have_device) {
+	// when a vibration port is present would rate-limit the device-backed ports to exactly 1x and
+	// prevent their SDL queues from building an underrun cushion.
+	if (blocking && max_wait_time != 0 && !any_port_has_device) {
 		Common::Thread::SleepMicro(max_wait_time);
 	}
 

src/libs/audio_internal.h

@@ -26,6 +26,7 @@ static constexpr int OUT_PORTS_MAX = 32;
 
 int      AudioOutOpen(int type, uint32_t samples_num, uint32_t freq, Format format);
 void     AudioOutClose(int handle);
+bool     AudioOutHasDevice(int handle);
 uint32_t AudioOutOutputs(const OutputParam* params, uint32_t num, bool blocking = true);
 
 } // namespace Libs::Audio::AudioInternal

src/libs/libAudio2.cpp

@@ -336,6 +336,17 @@ static AudioOut2PortStateEntry* audioout2_find_port_locked(AudioOut2PortHandle p
 	return nullptr;
 }
 
+static bool audioout2_context_has_queueable_device(AudioOut2ContextHandle ctx) {
+	Common::LockGuard lock(g_audioout2_port_mutex);
+	for (const auto& state: g_audioout2_ports) {
+		if (state.used && state.context == ctx && state.audio_handle > 0 &&
+		    state.pcm_data != nullptr && AudioInternal::AudioOutHasDevice(state.audio_handle)) {
+			return true;
+		}
+	}
+	return false;
+}
+
 static void audioout2_queue_context_audio(AudioOut2ContextHandle ctx, bool blocking) {
 	std::vector<AudioInternal::OutputParam> params;
 	params.reserve(AudioInternal::OUT_PORTS_MAX);
@@ -493,15 +504,23 @@ int KYTY_SYSV_ABI AudioOut2ContextPush(AudioOut2ContextHandle ctx, uint32_t bloc
 	uint32_t sleep_micros = audioout2_grain_micros(512);
 
 	for (;;) {
+		// Only a synchronous submission carrying PCM to a real device can rely on the SDL queue for
+		// pacing. Async pushes must retain queue-depth backpressure, and a handle without PCM (or a
+		// vibration/failed-open handle) has no downstream operation that can block this call.
+		const bool use_device_clock =
+		    blocking != 0 && audioout2_context_has_queueable_device(ctx);
+
 		g_audioout2_context_mutex.Lock();
 		if (auto* state = audioout2_find_context_locked(ctx); state != nullptr) {
 			audioout2_update_context_locked(state);
 			sleep_micros = audioout2_grain_micros(state->num_grains);
-			if (state->queued < state->queue_depth) {
+			if (state->queued < state->queue_depth || use_device_clock) {
 				if (state->queued == 0) {
 					state->last_update = LibKernel::KernelGetProcessTime();
 				}
-				state->queued++;
+				if (state->queued < state->queue_depth) {
+					state->queued++;
+				}
 				g_audioout2_context_mutex.Unlock();
 				audioout2_queue_context_audio(ctx, blocking != 0);
 				return OK;

tests/AudioOut2PortTests.cpp

@@ -19,6 +19,8 @@ namespace AudioOut2 = Libs::Audio::AudioOut2;
 std::mutex              g_device_mutex;
 std::condition_variable g_device_cv;
 std::vector<int>        g_live_devices;
+std::vector<int>        g_device_backed_handles;
+std::vector<bool>       g_output_blocking;
 int                     g_next_device  = 1;
 int                     g_open_waiters = 0;
 bool                    g_block_opens  = false;
@@ -61,6 +63,17 @@ struct PortState {
 	uint64_t reserved[6];
 };
 
+struct Attribute {
+	uint32_t    attribute_id;
+	int32_t     reserved;
+	const void* value;
+	size_t      value_size;
+};
+
+struct Pcm {
+	const void* data;
+};
+
 const auto* AsParam(const PortParam* param) {
 	return reinterpret_cast<const AudioOut2::AudioOut2PortParam*>(param);
 }
@@ -73,6 +86,10 @@ auto* AsState(PortState* state) {
 	return reinterpret_cast<AudioOut2::AudioOut2PortState*>(state);
 }
 
+const auto* AsAttribute(const Attribute* attribute) {
+	return reinterpret_cast<const AudioOut2::AudioOut2Attribute*>(attribute);
+}
+
 PortParam MakeParam(uint32_t data_format = 0x200) {
 	PortParam param {};
 	param.data_format   = data_format;
@@ -80,9 +97,9 @@ PortParam MakeParam(uint32_t data_format = 0x200) {
 	return param;
 }
 
-AudioOut2::AudioOut2ContextHandle CreateContext() {
+AudioOut2::AudioOut2ContextHandle CreateContext(uint32_t queue_depth = 4) {
 	ContextParam param {};
-	param.queue_depth                         = 4;
+	param.queue_depth                         = queue_depth;
 	param.num_grains                          = 512;
 	AudioOut2::AudioOut2ContextHandle context = 0;
 	Check(AudioOut2::AudioOut2ContextCreate(AsParam(&param), nullptr, 0, &context) == OK,
@@ -112,6 +129,23 @@ int LiveDeviceCount() {
 	return static_cast<int>(g_live_devices.size());
 }
 
+void SetPcm(AudioOut2::AudioOut2PortHandle port, const void* data) {
+	const Pcm       pcm {data};
+	const Attribute attribute {0, 0, &pcm, sizeof(pcm)};
+	Check(AudioOut2::AudioOut2PortSetAttributes(port, AsAttribute(&attribute), 1) == OK,
+	      "setting PCM failed");
+}
+
+void ResetOutputCalls() {
+	std::lock_guard lock(g_device_mutex);
+	g_output_blocking.clear();
+}
+
+std::vector<bool> OutputCalls() {
+	std::lock_guard lock(g_device_mutex);
+	return g_output_blocking;
+}
+
 void TestSlotReuse() {
 	const auto context = CreateContext();
 	const auto param   = MakeParam();
@@ -202,14 +236,83 @@ void TestContextDestroyCancelsPendingCreate() {
 	Check(LiveDeviceCount() == 0, "cancelled port create leaked a device");
 }
 
+void TestSynchronousDevicePushBypassesModelledQueue() {
+	const auto context = CreateContext(1);
+	const auto param   = MakeParam();
+	AudioOut2::AudioOut2PortHandle port = 0;
+	Check(AudioOut2::AudioOut2PortCreate(context, AsParam(&param), &port) == OK,
+	      "device port create failed");
+
+	uint32_t pcm[512] {};
+	SetPcm(port, pcm);
+	ResetOutputCalls();
+
+	Check(AudioOut2::AudioOut2ContextPush(context, 1) == OK, "first sync push failed");
+	Check(AudioOut2::AudioOut2ContextPush(context, 1) == OK,
+	      "device-paced sync push was blocked by modelled queue");
+	const auto calls = OutputCalls();
+	Check(calls.size() == 2, "sync pushes did not reach the device backend");
+	Check(calls[0] && calls[1], "sync pushes lost their blocking mode");
+
+	AudioOut2::AudioOut2PortDestroy(port);
+	AudioOut2::AudioOut2ContextDestroy(context);
+}
+
+void TestAsynchronousDevicePushKeepsQueueBounded() {
+	const auto context = CreateContext(1);
+	const auto param   = MakeParam();
+	AudioOut2::AudioOut2PortHandle port = 0;
+	Check(AudioOut2::AudioOut2PortCreate(context, AsParam(&param), &port) == OK,
+	      "device port create failed");
+
+	uint32_t pcm[512] {};
+	SetPcm(port, pcm);
+	ResetOutputCalls();
+
+	Check(AudioOut2::AudioOut2ContextPush(context, 0) == OK, "first async push failed");
+	Check(AudioOut2::AudioOut2ContextPush(context, 0) != OK,
+	      "full async queue accepted another buffer");
+	const auto calls = OutputCalls();
+	Check(calls.size() == 1 && !calls[0], "rejected async push reached the device backend");
+
+	uint32_t queued    = 0;
+	uint32_t available = 0;
+	Check(AudioOut2::AudioOut2ContextGetQueueLevel(context, &queued, &available) == OK,
+	      "queue-level query failed");
+	Check(queued == 1 && available == 0, "async queue level does not match accepted pushes");
+
+	AudioOut2::AudioOut2PortDestroy(port);
+	AudioOut2::AudioOut2ContextDestroy(context);
+}
+
+void TestHandleWithoutPcmDoesNotBypassQueue() {
+	const auto context = CreateContext(1);
+	const auto param   = MakeParam();
+	AudioOut2::AudioOut2PortHandle port = 0;
+	Check(AudioOut2::AudioOut2PortCreate(context, AsParam(&param), &port) == OK,
+	      "device port create failed");
+	ResetOutputCalls();
+
+	Check(AudioOut2::AudioOut2ContextPush(context, 1) == OK, "empty sync push failed");
+	Check(AudioOut2::AudioOut2ContextPush(context, 0) != OK,
+	      "handle without PCM bypassed queue backpressure");
+	Check(OutputCalls().empty(), "empty push reached the device backend");
+
+	AudioOut2::AudioOut2PortDestroy(port);
+	AudioOut2::AudioOut2ContextDestroy(context);
+}
+
 } // namespace
 
 namespace Libs::Audio::AudioInternal {
 
-int AudioOutOpen(int /*type*/, uint32_t /*samples_num*/, uint32_t /*freq*/, Format /*format*/) {
+int AudioOutOpen(int type, uint32_t /*samples_num*/, uint32_t /*freq*/, Format /*format*/) {
 	std::unique_lock lock(g_device_mutex);
 	const int        handle = g_next_device++;
 	g_live_devices.push_back(handle);
+	if (type != 10) {
+		g_device_backed_handles.push_back(handle);
+	}
 	g_open_waiters++;
 	g_device_cv.notify_all();
 	g_device_cv.wait(lock, []() { return !g_block_opens; });
@@ -222,9 +325,22 @@ void AudioOutClose(int handle) {
 	if (it != g_live_devices.end()) {
 		g_live_devices.erase(it);
 	}
+	const auto device_it =
+	    std::find(g_device_backed_handles.begin(), g_device_backed_handles.end(), handle);
+	if (device_it != g_device_backed_handles.end()) {
+		g_device_backed_handles.erase(device_it);
+	}
 }
 
-uint32_t AudioOutOutputs(const OutputParam* /*params*/, uint32_t /*num*/, bool /*blocking*/) {
+bool AudioOutHasDevice(int handle) {
+	std::lock_guard lock(g_device_mutex);
+	return std::find(g_device_backed_handles.begin(), g_device_backed_handles.end(), handle) !=
+	       g_device_backed_handles.end();
+}
+
+uint32_t AudioOutOutputs(const OutputParam* /*params*/, uint32_t /*num*/, bool blocking) {
+	std::lock_guard lock(g_device_mutex);
+	g_output_blocking.push_back(blocking);
 	return 0;
 }
 
@@ -244,6 +360,9 @@ int main() {
 	TestFullTableRecovers();
 	TestConcurrentCreates();
 	TestContextDestroyCancelsPendingCreate();
+	TestSynchronousDevicePushBypassesModelledQueue();
+	TestAsynchronousDevicePushKeepsQueueBounded();
+	TestHandleWithoutPcmDoesNotBypassQueue();
 	std::printf("AudioOut2PortTests: all cases passed\n");
 	return 0;
 }