services/pipewire: cache route device volumes to initialize nodes

Nodes referencing a device can be bound later than the device is
bound. If this happens, the node will not receive an initial route
device volume change event. This change caches the last known route
device volume and initializes the device with it if present.

changelog/next.md

@@ -24,6 +24,7 @@ set shell id.
 
 - Fixed volume control breaking with pipewire pro audio mode.
 - Fixed escape sequence handling in desktop entries.
+- Fixed volumes not initializing if a pipewire device was already loaded before its node.
 
 ## Packaging Changes
 

src/services/pipewire/device.cpp

@@ -125,12 +125,22 @@ void PwDevice::addDeviceIndexPairs(const spa_pod* param) {
 	// Insert into the main map as well, staging's purpose is to remove old entries.
 	this->routeDeviceIndexes.insert(device, index);
 
+	// Used for initial node volume if the device is bound before the node
+	// (e.g. multiple nodes pointing to the same device)
+	this->routeDeviceVolumes.insert(device, volumeProps);
+
 	qCDebug(logDevice).nospace() << "Registered device/index pair for " << this
 	                             << ": [device: " << device << ", index: " << index << ']';
 
 	emit this->routeVolumesChanged(device, volumeProps);
 }
 
+bool PwDevice::tryLoadVolumeProps(qint32 routeDevice, PwVolumeProps& volumeProps) {
+	if (!this->routeDeviceVolumes.contains(routeDevice)) return false;
+	volumeProps = this->routeDeviceVolumes.value(routeDevice);
+	return true;
+}
+
 void PwDevice::polled() {
 	// It is far more likely that the list content has not come in yet than it having no entries,
 	// and there isn't a way to check in the case that there *aren't* actually any entries.

src/services/pipewire/device.hpp

@@ -32,6 +32,8 @@ public:
 	void waitForDevice();
 	[[nodiscard]] bool waitingForDevice() const;
 
+	[[nodiscard]] bool tryLoadVolumeProps(qint32 routeDevice, PwVolumeProps& volumeProps);
+
 signals:
 	void deviceReady();
 	void routeVolumesChanged(qint32 routeDevice, const PwVolumeProps& volumeProps);
@@ -46,6 +48,7 @@ private:
 	onParam(void* data, qint32 seq, quint32 id, quint32 index, quint32 next, const spa_pod* param);
 
 	QHash<qint32, qint32> routeDeviceIndexes;
+	QHash<qint32, PwVolumeProps> routeDeviceVolumes;
 	QList<qint32> stagingIndexes;
 	void addDeviceIndexPairs(const spa_pod* param);
 

src/services/pipewire/node.cpp

@@ -218,6 +218,7 @@ void PwNode::onInfo(void* data, const pw_node_info* info) {
 				}
 
 				self->routeDevice = id;
+				if (self->boundData) self->boundData->onDeviceChanged();
 			} else {
 				qCCritical(logNode) << self << "has attached device" << self->device
 				                    << "but no card.profile.device property.";
@@ -277,6 +278,15 @@ PwNodeBoundAudio::PwNodeBoundAudio(PwNode* node): QObject(node), node(node) {
 	}
 }
 
+void PwNodeBoundAudio::onDeviceChanged() {
+	PwVolumeProps volumeProps;
+	if (this->node->device->tryLoadVolumeProps(this->node->routeDevice, volumeProps)) {
+		qCDebug(logNode) << "Initializing volume props for" << this->node
+		                 << "with known values from backing device.";
+		this->updateVolumeProps(volumeProps);
+	}
+}
+
 void PwNodeBoundAudio::onInfo(const pw_node_info* info) {
 	if ((info->change_mask & PW_NODE_CHANGE_MASK_PARAMS) != 0) {
 		for (quint32 i = 0; i < info->n_params; i++) {
@@ -299,7 +309,8 @@ void PwNodeBoundAudio::onSpaParam(quint32 id, quint32 index, const spa_pod* para
 	if (id == SPA_PARAM_Props && index == 0) {
 		if (this->node->shouldUseDevice()) {
 			qCDebug(logNode) << "Skipping node volume props update for" << this->node
-			                 << "in favor of device updates.";
+			                 << "in favor of device updates from routeDevice" << this->node->routeDevice
+			                 << "of" << this->node->device;
 			return;
 		}
 

src/services/pipewire/node.hpp

@@ -169,6 +169,7 @@ public:
 	virtual ~PwNodeBoundData() = default;
 	Q_DISABLE_COPY_MOVE(PwNodeBoundData);
 
+	virtual void onDeviceChanged() {};
 	virtual void onInfo(const pw_node_info* /*info*/) {}
 	virtual void onSpaParam(quint32 /*id*/, quint32 /*index*/, const spa_pod* /*param*/) {}
 	virtual void onUnbind() {}
@@ -182,6 +183,7 @@ class PwNodeBoundAudio
 public:
 	explicit PwNodeBoundAudio(PwNode* node);
 
+	void onDeviceChanged() override;
 	void onInfo(const pw_node_info* info) override;
 	void onSpaParam(quint32 id, quint32 index, const spa_pod* param) override;
 	void onUnbind() override;