fix: prevent audio disconnect from blocking new WebRTC sessions

When an old connection closed while a new one started, the audio cleanup
would hold audioMutex for up to 37 seconds during CGO disconnect calls,
blocking the new session from initializing.

Use capture-clear-release pattern to minimize mutex hold time:
- Capture references to sources/relays while holding mutex
- Clear globals immediately so new sessions can proceed
- Release mutex before calling blocking Stop/Disconnect operations

This eliminates the 37-second hang during connection transitions.

Makefile

@@ -205,12 +205,14 @@ lint-go-fix: build_audio_deps
 # Run UI linting locally (mirrors GitHub workflow ui-lint.yml)
 lint-ui:
 	@echo "Running UI lint..."
-	@cd ui && npm ci && npm run lint
+	@cd ui && npm ci
+	@cd ui && npm run lint
 
 # Run UI linting with auto-fix
 lint-ui-fix:
 	@echo "Running UI lint with auto-fix..."
-	@cd ui && npm ci && npm run lint:fix
+	@cd ui && npm ci
+	@cd ui && npm run lint:fix
 
 # Legacy alias for UI linting (for backward compatibility)
 ui-lint: lint-ui

audio.go

@@ -14,7 +14,7 @@ import (
 var (
 	audioMutex         sync.Mutex
 	outputSource       audio.AudioSource
-	inputSource        atomic.Pointer[audio.AudioSource]
+	inputSource        audio.AudioSource
 	outputRelay        *audio.OutputRelay
 	inputRelay         *audio.InputRelay
 	audioInitialized   bool
@@ -63,15 +63,13 @@ func startAudio() error {
 
 	// Start input audio if not running, USB audio enabled, and input enabled
 	ensureConfigLoaded()
-	if inputSource.Load() == nil && audioInputEnabled.Load() && config.UsbDevices != nil && config.UsbDevices.Audio {
+	if inputSource == nil && audioInputEnabled.Load() && config.UsbDevices != nil && config.UsbDevices.Audio {
 		alsaPlaybackDevice := "hw:1,0" // USB speakers
 
 		// Create CGO audio source
-		newInputSource := audio.NewCgoInputSource(alsaPlaybackDevice)
-		var audioSrc audio.AudioSource = newInputSource
-		inputSource.Store(&audioSrc)
+		inputSource = audio.NewCgoInputSource(alsaPlaybackDevice)
 
-		inputRelay = audio.NewInputRelay(newInputSource)
+		inputRelay = audio.NewInputRelay(inputSource)
 		if err := inputRelay.Start(); err != nil {
 			audioLogger.Error().Err(err).Msg("Failed to start input relay")
 		}
@@ -80,41 +78,31 @@ func startAudio() error {
 	return nil
 }
 
-// stopOutputLocked stops output audio (assumes mutex is held)
-func stopOutputLocked() {
-	if outputRelay != nil {
-		outputRelay.Stop()
-		outputRelay = nil
-	}
-	if outputSource != nil {
-		outputSource.Disconnect()
-		outputSource = nil
-	}
-}
-
-// stopInputLocked stops input audio (assumes mutex is held)
-func stopInputLocked() {
-	if inputRelay != nil {
-		inputRelay.Stop()
-		inputRelay = nil
-	}
-	if source := inputSource.Load(); source != nil {
-		(*source).Disconnect()
-		inputSource.Store(nil)
-	}
-}
-
-// stopAudioLocked stops all audio (assumes mutex is held)
-func stopAudioLocked() {
-	stopOutputLocked()
-	stopInputLocked()
-}
-
-// stopAudio stops all audio
 func stopAudio() {
 	audioMutex.Lock()
-	defer audioMutex.Unlock()
-	stopAudioLocked()
+	outRelay := outputRelay
+	outSource := outputSource
+	inRelay := inputRelay
+	inSource := inputSource
+	outputRelay = nil
+	outputSource = nil
+	inputRelay = nil
+	inputSource = nil
+	audioMutex.Unlock()
+
+	// Disconnect outside mutex to avoid blocking new sessions during CGO calls
+	if outRelay != nil {
+		outRelay.Stop()
+	}
+	if outSource != nil {
+		outSource.Disconnect()
+	}
+	if inRelay != nil {
+		inRelay.Stop()
+	}
+	if inSource != nil {
+		inSource.Disconnect()
+	}
 }
 
 func onWebRTCConnect() {
@@ -171,8 +159,18 @@ func SetAudioOutputEnabled(enabled bool) error {
 		}
 	} else {
 		audioMutex.Lock()
-		defer audioMutex.Unlock()
-		stopOutputLocked()
+		outRelay := outputRelay
+		outSource := outputSource
+		outputRelay = nil
+		outputSource = nil
+		audioMutex.Unlock()
+
+		if outRelay != nil {
+			outRelay.Stop()
+		}
+		if outSource != nil {
+			outSource.Disconnect()
+		}
 	}
 
 	return nil
@@ -190,8 +188,18 @@ func SetAudioInputEnabled(enabled bool) error {
 		}
 	} else {
 		audioMutex.Lock()
-		defer audioMutex.Unlock()
-		stopInputLocked()
+		inRelay := inputRelay
+		inSource := inputSource
+		inputRelay = nil
+		inputSource = nil
+		audioMutex.Unlock()
+
+		if inRelay != nil {
+			inRelay.Stop()
+		}
+		if inSource != nil {
+			inSource.Disconnect()
+		}
 	}
 
 	return nil
@@ -240,22 +248,23 @@ func handleInputTrackForSession(track *webrtc.TrackRemote) {
 			continue // Drop frame but keep reading
 		}
 
-		// Get source atomically (hot path optimization)
-		source := inputSource.Load()
+		// Get source in single mutex operation (hot path optimization)
+		audioMutex.Lock()
+		source := inputSource
+		audioMutex.Unlock()
 
 		if source == nil {
 			continue // No relay, drop frame but keep reading
 		}
 
-		if !(*source).IsConnected() {
-			if err := (*source).Connect(); err != nil {
+		if !source.IsConnected() {
+			if err := source.Connect(); err != nil {
 				continue
 			}
 		}
 
-		if err := (*source).WriteMessage(0, opusData); err != nil {
-			(*source).Disconnect()
-			audioLogger.Warn().Err(err).Str("track_id", myTrackID).Msg("failed to write audio message")
+		if err := source.WriteMessage(0, opusData); err != nil {
+			source.Disconnect()
 		}
 	}
 }

jsonrpc.go

@@ -894,11 +894,20 @@ func rpcGetUsbDevices() (usbgadget.Devices, error) {
 func updateUsbRelatedConfig(wasAudioEnabled bool) error {
 	ensureConfigLoaded()
 
-	// Stop input audio before USB reconfiguration (input uses USB)
 	audioMutex.Lock()
-	stopInputLocked()
+	inRelay := inputRelay
+	inSource := inputSource
+	inputRelay = nil
+	inputSource = nil
 	audioMutex.Unlock()
 
+	if inRelay != nil {
+		inRelay.Stop()
+	}
+	if inSource != nil {
+		inSource.Disconnect()
+	}
+
 	if err := gadget.UpdateGadgetConfig(); err != nil {
 		return fmt.Errorf("failed to write gadget config: %w", err)
 	}

main.go

@@ -133,7 +133,7 @@ func Main() {
 	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
 	<-sigs
 
-	logger.Log().Msg("JetKVM Shutting Down")
+	logger.Info().Msg("JetKVM Shutting Down")
 
 	stopAudio()
 

ui/src/routes/devices.$id.settings.audio.tsx

@@ -12,19 +12,19 @@ import notifications from "../notifications";
 
 export default function SettingsAudioRoute() {
   const { send } = useJsonRpc();
-  const settings = useSettingsStore();
+  const { setAudioOutputEnabled, setAudioInputAutoEnable, audioOutputEnabled, audioInputAutoEnable  } = useSettingsStore();
 
   useEffect(() => {
     send("getAudioOutputEnabled", {}, (resp: JsonRpcResponse) => {
       if ("error" in resp) return;
-      settings.setAudioOutputEnabled(resp.result as boolean);
+      setAudioOutputEnabled(resp.result as boolean);
     });
 
     send("getAudioInputAutoEnable", {}, (resp: JsonRpcResponse) => {
       if ("error" in resp) return;
-      settings.setAudioInputAutoEnable(resp.result as boolean);
+      setAudioInputAutoEnable(resp.result as boolean);
     });
-  }, [send, settings]);
+  }, [send, setAudioOutputEnabled, setAudioInputAutoEnable]);
 
   const handleAudioOutputEnabledChange = (enabled: boolean) => {
     send("setAudioOutputEnabled", { enabled }, (resp: JsonRpcResponse) => {
@@ -35,7 +35,7 @@ export default function SettingsAudioRoute() {
         notifications.error(errorMsg);
         return;
       }
-      settings.setAudioOutputEnabled(enabled);
+      setAudioOutputEnabled(enabled);
       const successMsg = enabled ? m.audio_output_enabled() : m.audio_output_disabled();
       notifications.success(successMsg);
     });
@@ -47,7 +47,7 @@ export default function SettingsAudioRoute() {
         notifications.error(String(resp.error.data || m.unknown_error()));
         return;
       }
-      settings.setAudioInputAutoEnable(enabled);
+      setAudioInputAutoEnable(enabled);
       const successMsg = enabled
         ? m.audio_input_auto_enable_enabled()
         : m.audio_input_auto_enable_disabled();
@@ -67,7 +67,7 @@ export default function SettingsAudioRoute() {
           description={m.audio_settings_output_description()}
         >
           <Checkbox
-            checked={settings.audioOutputEnabled || false}
+            checked={audioOutputEnabled || false}
             onChange={(e) => handleAudioOutputEnabledChange(e.target.checked)}
           />
         </SettingsItem>
@@ -77,7 +77,7 @@ export default function SettingsAudioRoute() {
           description={m.audio_settings_auto_enable_microphone_description()}
         >
           <Checkbox
-            checked={settings.audioInputAutoEnable || false}
+            checked={audioInputAutoEnable || false}
             onChange={(e) => handleAudioInputAutoEnableChange(e.target.checked)}
           />
         </SettingsItem>