Fix Vulkan decoder probing on Nvidia using KMSDRM

app/streaming/streamutils.cpp

@@ -87,15 +87,30 @@ Uint32 StreamUtils::getPlatformWindowFlags()
 SDL_Window* StreamUtils::createTestWindow()
 {
     SDL_Window* testWindow;
+    Uint32 baseFlags = 0;
 
+    // Test windows are always hidden
+    baseFlags |= SDL_WINDOW_HIDDEN;
+
+    // Creating a Vulkan surface with KMSDRM requires finding a display mode
+    // that exactly matches the window size. This is not always possible,
+    // particularly with drivers (Nvidia) that only expose modes matching
+    // the current resolution (only differing by refresh rate). Fullscreen
+    // desktop mode ensures the window size exactly matches the display mode
+    // which prevents false Vulkan renderer failures during decoder probing.
+    if (QString(SDL_GetCurrentVideoDriver()) == "KMSDRM") {
+        baseFlags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
+    }
+
+    // Try to add the platform-specific flags first and fall back if that fails
     testWindow = SDL_CreateWindow("", 0, 0, 1280, 720,
-                                  SDL_WINDOW_HIDDEN | StreamUtils::getPlatformWindowFlags());
+                                  baseFlags | StreamUtils::getPlatformWindowFlags());
     if (!testWindow) {
         SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
                     "Failed to create test window with platform flags: %s",
                     SDL_GetError());
 
-        testWindow = SDL_CreateWindow("", 0, 0, 1280, 720, SDL_WINDOW_HIDDEN);
+        testWindow = SDL_CreateWindow("", 0, 0, 1280, 720, baseFlags);
         if (!testWindow) {
             return nullptr;
         }