X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=alsa_input.cpp;h=e96366b3a693074930154788b8da49671445bb5a;hb=a0e27555696d0c63e3d89e31ca8f4292dcf40179;hp=4e507f39cb374de0360d1beb6eeb5a06345b98e9;hpb=b590a9a091974607517a9f872e28cbfa65014e2a;p=nageru

diff --git a/alsa_input.cpp b/alsa_input.cpp
index 4e507f3..e96366b 100644
--- a/alsa_input.cpp
+++ b/alsa_input.cpp
@@ -45,8 +45,13 @@ bool set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_
 
 }  // namespace
 
-ALSAInput::ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback)
-	: device(device), sample_rate(sample_rate), num_channels(num_channels), audio_callback(audio_callback)
+ALSAInput::ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback, ALSAPool *parent_pool, unsigned internal_dev_index)
+	: device(device),
+	  sample_rate(sample_rate),
+	  num_channels(num_channels),
+	  audio_callback(audio_callback),
+	  parent_pool(parent_pool),
+	  internal_dev_index(internal_dev_index)
 {
 	die_on_error(device, snd_pcm_open(&pcm_handle, device, SND_PCM_STREAM_CAPTURE, 0));
 
@@ -132,7 +137,10 @@ void ALSAInput::stop_capture_thread()
 
 void ALSAInput::capture_thread_func()
 {
+	parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 	die_on_error("snd_pcm_start()", snd_pcm_start(pcm_handle));
+	parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::RUNNING);
+
 	uint64_t num_frames_output = 0;
 	while (!should_quit) {
 		int ret = snd_pcm_wait(pcm_handle, /*timeout=*/100);
@@ -167,6 +175,7 @@ void ALSAInput::capture_thread_func()
 		} while (!success);
 		num_frames_output += frames;
 	}
+	parent_pool->free_card(internal_dev_index);
 }
 
 int64_t ALSAInput::frames_to_pts(uint64_t n) const
@@ -187,7 +196,6 @@ ALSAPool::~ALSAPool()
 	for (Device &device : devices) {
 		if (device.input != nullptr) {
 			device.input->stop_capture_thread();
-			delete device.input;
 		}
 	}
 }
@@ -233,12 +241,78 @@ void ALSAPool::enumerate_devices()
 
 		// Enumerate all devices on this card.
 		for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
-			add_device(card_index, dev_index);
+			probe_device_with_retry(card_index, dev_index);
 		}
 	}
 }
 
-bool ALSAPool::add_device(unsigned card_index, unsigned dev_index)
+void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
+{
+	char address[256];
+	snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
+
+	lock_guard<mutex> lock(add_device_mutex);
+	if (add_device_tries_left.count(address)) {
+		// Some thread is already busy retrying this,
+		// so just reset its count.
+		add_device_tries_left[address] = num_retries;
+		return;
+	}
+
+	// Try (while still holding the lock) to add the device synchronously.
+	ProbeResult result = probe_device_once(card_index, dev_index);
+	if (result == ProbeResult::SUCCESS) {
+		return;
+	} else if (result == ProbeResult::FAILURE) {
+		return;
+	}
+	assert(result == ProbeResult::DEFER);
+
+	// Add failed for whatever reason (probably just that the device
+	// isn't up yet. Set up a count so that nobody else starts a thread,
+	// then start it ourselves.
+	fprintf(stderr, "Trying %s again in one second...\n", address);
+	add_device_tries_left[address] = num_retries;
+	thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
+}
+
+void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
+{
+	char address[256];
+	snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
+
+	for ( ;; ) {  // Termination condition within the loop.
+		sleep(1);
+
+		// See if there are any retries left.
+		lock_guard<mutex> lock(add_device_mutex);
+		if (!add_device_tries_left.count(address) ||
+		    add_device_tries_left[address] == 0) {
+			add_device_tries_left.erase(address);
+			fprintf(stderr, "Giving up probe of %s.\n", address);
+			return;
+		}
+
+		// Seemingly there were. Give it a try (we still hold the mutex).
+		ProbeResult result = probe_device_once(card_index, dev_index);
+		if (result == ProbeResult::SUCCESS) {
+			add_device_tries_left.erase(address);
+			fprintf(stderr, "Probe of %s succeeded.\n", address);
+			return;
+		} else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
+			add_device_tries_left.erase(address);
+			fprintf(stderr, "Giving up probe of %s.\n", address);
+			return;
+		}
+
+		// Failed again.
+		assert(result == ProbeResult::DEFER);
+		fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
+			address, add_device_tries_left[address]);
+	}
+}
+
+ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 {
 	char address[256];
 	snprintf(address, sizeof(address), "hw:%d", card_index);
@@ -246,7 +320,7 @@ bool ALSAPool::add_device(unsigned card_index, unsigned dev_index)
 	int err = snd_ctl_open(&ctl, address, 0);
 	if (err < 0) {
 		printf("%s: %s\n", address, snd_strerror(err));
-		return false;
+		return ALSAPool::ProbeResult::DEFER;
 	}
 	unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 
@@ -257,7 +331,8 @@ bool ALSAPool::add_device(unsigned card_index, unsigned dev_index)
 	snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 	if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 		// Not available for capture.
-		return false;
+		printf("%s: Not available for capture.\n", address);
+		return ALSAPool::ProbeResult::DEFER;
 	}
 
 	snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
@@ -279,54 +354,107 @@ bool ALSAPool::add_device(unsigned card_index, unsigned dev_index)
 		snd_pcm_t *pcm_handle;
 		int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 		if (err < 0) {
-			// TODO: When we go to hotplug support, we should support some
-			// retry here, as the device could legitimately be busy.
 			printf("%s: %s\n", address, snd_strerror(err));
-			return false;
+			return ALSAPool::ProbeResult::DEFER;
 		}
 		snd_pcm_hw_params_t *hw_params;
 		snd_pcm_hw_params_alloca(&hw_params);
 		unsigned sample_rate;
 		if (!set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 			snd_pcm_close(pcm_handle);
-			return false;
+			return ALSAPool::ProbeResult::DEFER;
 		}
 		err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 		if (err < 0) {
 			fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 				address, snd_strerror(err));
 			snd_pcm_close(pcm_handle);
-			return false;
+			return ALSAPool::ProbeResult::DEFER;
 		}
 		snd_pcm_close(pcm_handle);
 	}
 
 	if (num_channels == 0) {
 		printf("%s: No channel maps with channels\n", address);
-		return true;
+		return ALSAPool::ProbeResult::FAILURE;
 	}
 
 	snd_ctl_card_info_t *card_info;
 	snd_ctl_card_info_alloca(&card_info);
 	snd_ctl_card_info(ctl, card_info);
 
-	Device dev;
-	dev.address = address;
-	dev.name = snd_ctl_card_info_get_name(card_info);
-	dev.info = snd_pcm_info_get_name(pcm_info);
-	dev.num_channels = num_channels;
-	dev.state = Device::State::RUNNING;
-
 	lock_guard<mutex> lock(mu);
-	devices.push_back(std::move(dev));
-	return true;
+	unsigned internal_dev_index = find_free_device_index();
+	devices[internal_dev_index].address = address;
+	devices[internal_dev_index].name = snd_ctl_card_info_get_name(card_info);
+	devices[internal_dev_index].info = snd_pcm_info_get_name(pcm_info);
+	devices[internal_dev_index].num_channels = num_channels;
+	devices[internal_dev_index].state = Device::State::READY;
+
+	fprintf(stderr, "%s: Probed successfully.\n", address);
+
+	return ALSAPool::ProbeResult::SUCCESS;
 }
 
 void ALSAPool::init()
 {
+	thread(&ALSAPool::inotify_thread_func, this).detach();
 	enumerate_devices();
 }
 
+void ALSAPool::inotify_thread_func()
+{
+	int inotify_fd = inotify_init();
+	if (inotify_fd == -1) {
+		perror("inotify_init()");
+		fprintf(stderr, "No hotplug of ALSA devices available.\n");
+		return;
+	}
+
+	int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
+	if (watch_fd == -1) {
+		perror("inotify_add_watch()");
+		fprintf(stderr, "No hotplug of ALSA devices available.\n");
+		close(inotify_fd);
+		return;
+	}
+
+	int size = sizeof(inotify_event) + NAME_MAX + 1;
+	unique_ptr<char[]> buf(new char[size]);
+	for ( ;; ) {
+		int ret = read(inotify_fd, buf.get(), size);
+		if (ret < int(sizeof(inotify_event))) {
+			fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
+				int(ret));
+			close(watch_fd);
+			close(inotify_fd);
+			return;
+		}
+
+		for (int i = 0; i < ret; ) {
+			const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
+			i += sizeof(inotify_event) + event->len;
+
+			if (event->mask & IN_Q_OVERFLOW) {
+				fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
+				continue;
+			}
+			unsigned card, device;
+			char type;
+			if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
+				if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
+					printf("Deleted capture device: Card %u, device %u\n", card, device);
+					// TODO: Unplug.
+				}
+				if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
+					printf("Adding capture device: Card %u, device %u\n", card, device);
+					probe_device_with_retry(card, device);
+				}
+			}
+		}
+	}
+}
+
 void ALSAPool::reset_device(unsigned index)
 {
 	lock_guard<mutex> lock(mu);
@@ -338,7 +466,8 @@ void ALSAPool::reset_device(unsigned index)
 		inputs[index].reset();
 	} else {
 		// TODO: Put on a background thread instead of locking?
-		inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4)));
+		auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
+		inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 		inputs[index]->start_capture_thread();
 	}
 	device->input = inputs[index].get();
@@ -353,3 +482,46 @@ unsigned ALSAPool::get_capture_frequency(unsigned index)
 	else
 		return OUTPUT_FREQUENCY;
 }
+
+ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
+{
+	lock_guard<mutex> lock(mu);
+	assert(devices[index].held);
+	return devices[index].state;
+}
+
+void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
+{
+	lock_guard<mutex> lock(mu);
+	devices[index].state = state;
+}
+
+unsigned ALSAPool::find_free_device_index()
+{
+	for (unsigned i = 0; i < devices.size(); ++i) {
+		if (devices[i].state == Device::State::EMPTY) {
+			devices[i].state = Device::State::READY;
+			return i;
+		}
+	}
+	Device new_dev;
+	new_dev.state = Device::State::READY;
+	devices.push_back(new_dev);
+	inputs.emplace_back(nullptr);
+	return devices.size() - 1;
+}
+
+void ALSAPool::free_card(unsigned index)
+{
+	lock_guard<mutex> lock(mu);
+	if (devices[index].held) {
+		devices[index].state = Device::State::DEAD;
+	} else {
+		devices[index].state = Device::State::EMPTY;
+		inputs[index].reset();
+	}
+	while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
+		devices.pop_back();
+		inputs.pop_back();
+	}
+}