query gpu async (#1246)

* async advanced gpu query

* forrmat

src-tauri/src/lib.rs

@@ -542,6 +542,17 @@ pub fn run(cli_args: CliArgs) {
 
             initialize_core_logic(&app_handle);
 
+            // Pre-warm GPU/accelerator enumeration on a background thread.
+            // The first call into transcribe_rs::whisper_cpp::gpu::list_gpu_devices
+            // loads the Metal/Vulkan backend and probes devices, which can take
+            // several seconds. Without this, that cost is paid synchronously the
+            // first time the user opens the Advanced settings page (which calls
+            // the get_available_accelerators command), causing a UI freeze.
+            // Result is cached in a OnceLock inside the transcription manager.
+            std::thread::spawn(|| {
+                let _ = crate::managers::transcription::get_available_accelerators();
+            });
+
             // Hide tray icon if --no-tray was passed
             if cli_args.no_tray {
                 tray::set_tray_visibility(&app_handle, false);

src-tauri/src/shortcut/mod.rs

@@ -1143,8 +1143,15 @@ pub fn change_whisper_gpu_device(app: AppHandle, device: i32) -> Result<(), Stri
 }
 
 /// Return which accelerators and GPU devices are available for this build.
+///
+/// First-call cost is dominated by enumerating GPU devices through the
+/// whisper.cpp Metal/Vulkan backend, which loads dynamic libraries and
+/// probes hardware. Run it on the blocking pool so the webview thread
+/// stays responsive — see also the startup pre-warm in `lib.rs`.
 #[tauri::command]
 #[specta::specta]
-pub fn get_available_accelerators() -> crate::managers::transcription::AvailableAccelerators {
-    crate::managers::transcription::get_available_accelerators()
+pub async fn get_available_accelerators() -> crate::managers::transcription::AvailableAccelerators {
+    tauri::async_runtime::spawn_blocking(crate::managers::transcription::get_available_accelerators)
+        .await
+        .expect("get_available_accelerators panicked")
 }

src/bindings.ts

@@ -389,6 +389,11 @@ async changeWhisperGpuDevice(device: number) : Promise<Result<null, string>> {
 },
 /**
  * Return which accelerators and GPU devices are available for this build.
+ * 
+ * First-call cost is dominated by enumerating GPU devices through the
+ * whisper.cpp Metal/Vulkan backend, which loads dynamic libraries and
+ * probes hardware. Run it on the blocking pool so the webview thread
+ * stays responsive — see also the startup pre-warm in `lib.rs`.
  */
 async getAvailableAccelerators() : Promise<AvailableAccelerators> {
     return await TAURI_INVOKE("get_available_accelerators");