fix: address texture watchdog/probe review findings

- watchdog: compare the plugin's cumulative consumed counter against a
  snapshot taken when arming (re-arm was a no-op before), and judge on
  cumulative pushes + elapsed time so sparse damage-driven streams are
  still detected
- failure handling is idempotent (one record per breakage) and updates
  every render session like main_set_local_option does, not only the
  failing one; the fallback toast is not claimed for multi-display
  windows the soft path cannot rescue
- probe: skip when the consumed API is missing (old plugin) or a
  raster-stall is recorded (compositing could hang the main window);
  a fail verdict requires fresh frame timings and a non-minimized
  window; a pass never clears failed-raster-stall; toast only when
  texture rendering was effectively on; probe pixel is transparent
- raster-stall monitor: judge on frame-timing staleness (a mid-episode
  hang was undetectable before), gate on lifecycle/minimized/idle with
  a moving quiet anchor, threshold 30s, shared with the camera page;
  clear stateGlobal minimized flag on plain window restore
- adopt mismatched frame sizes only in multi-ui-session mode (legacy
  mode pairs frames loosely and could ping-pong between displays)
- drop the now-dead closeSession parameter from texture destroy();
  trim comments to repo style

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

flutter/lib/desktop/pages/remote_page.dart

@@ -21,6 +21,7 @@ import '../../common/shared_state.dart';
 import '../../utils/image.dart';
 import '../widgets/remote_toolbar.dart';
 import '../widgets/kb_layout_type_chooser.dart';
+import '../widgets/raster_stall_monitor.dart';
 import '../widgets/tabbar_widget.dart';
 import 'macos_full_screen_focus_recovery.dart';
 
@@ -156,7 +157,7 @@ class _RemotePageState extends State<RemotePage>
           widget.tabController?.state.listen(_onMacOSTabStateChanged);
     }
     Get.put<FFI>(_ffi, tag: widget.id);
-    _RasterStallMonitor.start();
+    RasterStallMonitor.start();
     _ffi.imageModel.addCallbackOnFirstImage((String peerId) {
       _ffi.canvasModel.activateLocalCursor();
       showKBLayoutTypeChooserIfNeeded(
@@ -648,7 +649,7 @@ class _RemotePageState extends State<RemotePage>
     // Clear callback reference to prevent memory leaks and stale references
     _ffi.inputModel.onRelativeMouseModeDisabled = null;
     // Relative mouse mode cleanup is centralized in FFI.close(closeSession: ...).
-    _ffi.textureModel.onRemotePageDispose(closeSession);
+    _ffi.textureModel.onRemotePageDispose();
     if (closeSession && !isMacOS) {
       // ensure we leave this session, this is a double check
       // enterOrLeave() is already called previously in _releaseMacOSRemoteInput() for macOS.
@@ -1404,44 +1405,3 @@ class CursorPaint extends StatelessWidget {
   }
 }
 
-/// Detects a hung raster thread: the UI keeps scheduling frames but the
-/// engine never reports completed frame timings. Rendering cannot be rescued
-/// in-process (software rendering needs the same raster thread), so this only
-/// records the breakage — the next launch then defaults texture rendering to
-/// off and the startup probe re-validates the environment.
-class _RasterStallMonitor {
-  static bool _started = false;
-  static bool _reported = false;
-  static DateTime? _lastTimings;
-  static DateTime? _scheduledSince;
-
-  static void start() {
-    if (_started || isWeb) return;
-    _started = true;
-    SchedulerBinding.instance.addTimingsCallback((_) {
-      _lastTimings = DateTime.now();
-    });
-    Timer.periodic(const Duration(seconds: 2), (_) {
-      if (_reported) return;
-      // A minimized window legitimately stops producing frame timings.
-      if (stateGlobal.isMinimized ||
-          !SchedulerBinding.instance.hasScheduledFrame) {
-        _scheduledSince = null;
-        return;
-      }
-      final now = DateTime.now();
-      _scheduledSince ??= now;
-      final lastTimings = _lastTimings;
-      final stalled =
-          now.difference(_scheduledSince!) > const Duration(seconds: 10) &&
-              (lastTimings == null || lastTimings.isBefore(_scheduledSince!));
-      if (stalled) {
-        _reported = true;
-        bind.mainSetLocalOption(
-            key: kOptionTextureRenderHealth, value: 'failed-raster-stall');
-        debugPrint(
-            'raster thread stall detected, texture rendering disabled for next launch');
-      }
-    });
-  }
-}

flutter/lib/desktop/pages/view_camera_page.dart

@@ -19,6 +19,7 @@ import '../../common/shared_state.dart';
 import '../../utils/image.dart';
 import '../widgets/remote_toolbar.dart';
 import '../widgets/kb_layout_type_chooser.dart';
+import '../widgets/raster_stall_monitor.dart';
 import '../widgets/tabbar_widget.dart';
 
 import 'package:flutter_hbb/native/custom_cursor.dart'
@@ -102,6 +103,7 @@ class _ViewCameraPageState extends State<ViewCameraPage>
     super.initState();
     _ffi = FFI(widget.sessionId);
     Get.put<FFI>(_ffi, tag: widget.id);
+    RasterStallMonitor.start();
     _ffi.imageModel.addCallbackOnFirstImage((String peerId) {
       showKBLayoutTypeChooserIfNeeded(
           _ffi.ffiModel.pi.platform, _ffi.dialogManager);
@@ -222,7 +224,7 @@ class _ViewCameraPageState extends State<ViewCameraPage>
     // https://github.com/flutter/flutter/issues/64935
     super.dispose();
     debugPrint("VIEW CAMERA PAGE dispose session $sessionId ${widget.id}");
-    _ffi.textureModel.onViewCameraPageDispose(closeSession);
+    _ffi.textureModel.onViewCameraPageDispose();
     if (closeSession) {
       // ensure we leave this session, this is a double check
       _ffi.inputModel.enterOrLeave(false);

flutter/lib/desktop/widgets/raster_stall_monitor.dart

@@ -0,0 +1,52 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/scheduler.dart';
+
+import '../../common.dart';
+import '../../consts.dart';
+import '../../models/platform_model.dart';
+import '../../models/state_model.dart';
+
+/// Records a hung raster thread (frames continuously scheduled but no frame
+/// timings delivered for 30s) in `texture-render-health`; a hang cannot be
+/// rescued in-process, so the next launch defaults texture rendering off.
+class RasterStallMonitor {
+  static bool _started = false;
+  static bool _reported = false;
+  static DateTime? _lastTimings;
+  static DateTime _lastQuiet = DateTime.now();
+
+  static void start() {
+    if (_started || isWeb) return;
+    _started = true;
+    SchedulerBinding.instance.addTimingsCallback((_) {
+      _lastTimings = DateTime.now();
+    });
+    Timer.periodic(const Duration(seconds: 2), (_) {
+      if (_reported) return;
+      final now = DateTime.now();
+      final lifecycle = SchedulerBinding.instance.lifecycleState;
+      // Minimized/inactive (incl. screen lock) or idle (nothing scheduled):
+      // no timings is legitimate, keep moving the quiet anchor forward.
+      if (stateGlobal.isMinimized ||
+          (lifecycle != null && lifecycle != AppLifecycleState.resumed) ||
+          !SchedulerBinding.instance.hasScheduledFrame) {
+        _lastQuiet = now;
+        return;
+      }
+      var ref = _lastQuiet;
+      final lastTimings = _lastTimings;
+      if (lastTimings != null && lastTimings.isAfter(ref)) {
+        ref = lastTimings;
+      }
+      if (now.difference(ref) > const Duration(seconds: 30)) {
+        _reported = true;
+        bind.mainSetLocalOption(
+            key: kOptionTextureRenderHealth, value: 'failed-raster-stall');
+        debugPrint(
+            'raster thread stall detected, texture rendering disabled for next launch');
+      }
+    });
+  }
+}

flutter/lib/desktop/widgets/tabbar_widget.dart

@@ -405,6 +405,13 @@ class _DesktopTabState extends State<DesktopTab>
     super.onWindowUnmaximize();
   }
 
+  @override
+  void onWindowRestore() {
+    // A plain restore (no maximize involved) must clear the minimized flag.
+    stateGlobal.setMinimized(false);
+    super.onWindowRestore();
+  }
+
   _saveFrame({bool? flush}) async {
     try {
       if (tabType == DesktopTabType.main) {

flutter/lib/desktop/widgets/texture_render_probe.dart

@@ -6,15 +6,14 @@ import 'package:flutter/scheduler.dart';
 import '../../common.dart';
 import '../../consts.dart';
 import '../../models/platform_model.dart';
+import '../../models/state_model.dart';
 
 import 'package:texture_rgba_renderer/texture_rgba_renderer.dart'
     if (dart.library.html) 'package:flutter_hbb/web/texture_rgba_renderer.dart';
 
 /// Startup probe: renders one frame through a 1x1 external texture and
-/// verifies the engine consumed it. The verdict is recorded in
-/// `texture-render-health` — a failure turns texture rendering off before the
-/// first session goes black, a pass clears a stale failure (self-healing
-/// after a driver/OS fix). Mounted once, in the main window.
+/// records in `texture-render-health` whether the engine consumed it, so a
+/// broken environment is detected before the first session goes black.
 class TextureRenderProbe extends StatefulWidget {
   const TextureRenderProbe({Key? key}) : super(key: key);
 
@@ -31,12 +30,24 @@ class _TextureRenderProbeState extends State<TextureRenderProbe> {
   Timer? _timer;
   int _ticks = 0;
   bool _sawTimings = false;
+  bool _wasEffectiveOn = false;
+  DateTime? _lastTimings;
 
   @override
   void initState() {
     super.initState();
     if (_ranThisLaunch || isWeb || !isDesktop) return;
     _ranThisLaunch = true;
+    if (bind.isIncomingOnly()) return;
+    // An old plugin without the consumed counter cannot be judged, and a
+    // recorded raster-stall means compositing a texture may hang this window.
+    if (!bind.mainTextureRenderProbeSupported()) return;
+    if (bind
+        .mainGetLocalOption(key: kOptionTextureRenderHealth)
+        .startsWith('failed-raster-stall')) {
+      return;
+    }
+    _wasEffectiveOn = bind.mainGetUseTextureRender();
     // Only probe after the window has really rendered a frame: a hidden
     // window (silent/tray start) must not record a false failure.
     SchedulerBinding.instance.addTimingsCallback(_onTimings);
@@ -49,9 +60,9 @@ class _TextureRenderProbeState extends State<TextureRenderProbe> {
   }
 
   void _onTimings(List<FrameTiming> timings) {
+    _lastTimings = DateTime.now();
     if (_sawTimings) return;
     _sawTimings = true;
-    SchedulerBinding.instance.removeTimingsCallback(_onTimings);
     _start();
   }
 
@@ -75,7 +86,11 @@ class _TextureRenderProbeState extends State<TextureRenderProbe> {
       if (bind.mainGetTextureProbeConsumed(ptr: _ptr) > 0) {
         _finish(true);
       } else if (_ticks >= 10) {
-        _finish(false);
+        // Only a window that is visibly compositing can prove a failure.
+        final timingsFresh = _lastTimings != null &&
+            DateTime.now().difference(_lastTimings!) <
+                const Duration(milliseconds: 1500);
+        _finish(!stateGlobal.isMinimized && timingsFresh ? false : null);
       }
     });
   }
@@ -83,17 +98,22 @@ class _TextureRenderProbeState extends State<TextureRenderProbe> {
   void _finish(bool? ok) {
     _timer?.cancel();
     _timer = null;
+    SchedulerBinding.instance.removeTimingsCallback(_onTimings);
     if (ok != null) {
       final old = bind.mainGetLocalOption(key: kOptionTextureRenderHealth);
       if (ok) {
-        if (old != 'ok') {
+        // A 1x1 probe pass disproves the black-texture class, not a
+        // raster-stall under load; that record only clears via the toggle.
+        if (old != 'ok' && !old.startsWith('failed-raster-stall')) {
           bind.mainSetLocalOption(key: kOptionTextureRenderHealth, value: 'ok');
         }
       } else if (!old.startsWith('failed')) {
         debugPrint('texture render probe failed, disabling texture rendering');
         bind.mainSetLocalOption(
             key: kOptionTextureRenderHealth, value: 'failed-probe');
-        showToast(translate('texture-render-fallback-tip'));
+        if (_wasEffectiveOn) {
+          showToast(translate('texture-render-fallback-tip'));
+        }
       }
     }
     if (_textureKey != -1) {
@@ -111,6 +131,7 @@ class _TextureRenderProbeState extends State<TextureRenderProbe> {
   @override
   void dispose() {
     _timer?.cancel();
+    SchedulerBinding.instance.removeTimingsCallback(_onTimings);
     if (_textureKey != -1) {
       _renderer.closeTexture(_textureKey);
       _textureKey = -1;
@@ -121,8 +142,8 @@ class _TextureRenderProbeState extends State<TextureRenderProbe> {
   @override
   Widget build(BuildContext context) {
     if (_textureId == -1) return const SizedBox.shrink();
-    // Must actually composite for the engine to sample the texture; 1x1 in a
-    // corner is imperceptible.
+    // Must actually composite for the engine to sample the texture; the
+    // pushed pixel is fully transparent.
     return IgnorePointer(
       child: SizedBox(
           width: 1, height: 1, child: Texture(textureId: _textureId)),

flutter/lib/models/desktop_render_texture.dart

@@ -52,15 +52,14 @@ class _PixelbufferTexture {
     });
   }
 
-  destroy(bool closeSession, FFI ffi) async {
+  destroy(FFI ffi) async {
     _closed = true;
     if (!_destroying && _textureKey != -1 && _sessionId != null) {
       _destroying = true;
       if (_ptr != 0) {
-        // Compare-and-clear: clears only if Rust still holds this pointer, so
-        // a registration a new window has already made stays intact (#8016).
-        // Returning from this synchronous call also guarantees no push
-        // through the old pointer is still in flight.
+        // Compare-and-clear: only clears if Rust still holds this pointer
+        // (#8016-safe); returning from this synchronous call also means no
+        // push through the old pointer is still in flight.
         platformFFI.unregisterPixelbufferTexture(_sessionId!, display, _ptr);
         _ptr = 0;
       }
@@ -122,7 +121,7 @@ class _GpuTexture {
     }
   }
 
-  destroy(bool closeSession, FFI ffi) async {
+  destroy(FFI ffi) async {
     // must stop texture render, render unregistered texture cause crash
     _closed = true;
     if (!_destroying && support && _sessionId != null && _textureId != -1) {
@@ -229,11 +228,11 @@ class TextureModel {
     tryRemoveTexture(int idx) {
       _control.remove(idx);
       if (_pixelbufferRenderTextures.containsKey(idx)) {
-        _pixelbufferRenderTextures[idx]!.destroy(true, ffi);
+        _pixelbufferRenderTextures[idx]!.destroy(ffi);
         _pixelbufferRenderTextures.remove(idx);
       }
       if (_gpuRenderTextures.containsKey(idx)) {
-        _gpuRenderTextures[idx]!.destroy(true, ffi);
+        _gpuRenderTextures[idx]!.destroy(ffi);
         _gpuRenderTextures.remove(idx);
       }
     }
@@ -253,25 +252,25 @@ class TextureModel {
     }
   }
 
-  onRemotePageDispose(bool closeSession) async {
+  onRemotePageDispose() async {
     final ffi = parent.target;
     if (ffi == null) return;
     for (final texture in _pixelbufferRenderTextures.values) {
-      await texture.destroy(closeSession, ffi);
+      await texture.destroy(ffi);
     }
     for (final texture in _gpuRenderTextures.values) {
-      await texture.destroy(closeSession, ffi);
+      await texture.destroy(ffi);
     }
   }
 
-  onViewCameraPageDispose(bool closeSession) async {
+  onViewCameraPageDispose() async {
     final ffi = parent.target;
     if (ffi == null) return;
     for (final texture in _pixelbufferRenderTextures.values) {
-      await texture.destroy(closeSession, ffi);
+      await texture.destroy(ffi);
     }
     for (final texture in _gpuRenderTextures.values) {
-      await texture.destroy(closeSession, ffi);
+      await texture.destroy(ffi);
     }
   }
 

flutter/lib/web/bridge.dart

@@ -1462,6 +1462,10 @@ class RustdeskImpl {
       required int ptr,
       dynamic hint}) {}
 
+  bool mainTextureRenderProbeSupported({dynamic hint}) {
+    return false;
+  }
+
   void mainPushTextureProbeFrame({required int ptr, dynamic hint}) {}
 
   int mainGetTextureProbeConsumed({required int ptr, dynamic hint}) {

src/flutter.rs

@@ -288,38 +288,44 @@ struct DisplaySessionInfo {
     gpu_output_ptr: usize,
     notify_render_type: Option<RenderType>,
     // Watchdog: frames pushed to a texture the engine never consumes mean
-    // texture rendering is broken on this machine (black view while the
-    // connection works). Armed until the first consumption is observed, so a
-    // later minimized window cannot false-positive.
+    // texture rendering is broken (black view on a live connection). Armed
+    // until a consumption is observed since arming.
     pushed_count: u64,
-    watchdog_pushed_at_sample: u64,
+    watchdog_consumed_base: Option<u64>,
+    watchdog_since: Option<Instant>,
     watchdog_last_sample: Option<Instant>,
-    watchdog_stall_windows: u32,
     watchdog_armed: bool,
 }
 
 impl DisplaySessionInfo {
     fn reset_watchdog(&mut self) {
         self.pushed_count = 0;
-        self.watchdog_pushed_at_sample = 0;
+        self.watchdog_consumed_base = None;
+        self.watchdog_since = None;
         self.watchdog_last_sample = None;
-        self.watchdog_stall_windows = 0;
         self.watchdog_armed = true;
     }
 
-    // Returns true when texture rendering is deemed broken: >=3 sampled
-    // seconds in which frames kept being pushed but none was ever consumed.
+    // The plugin counter is cumulative and never resets, so compare against a
+    // snapshot taken when arming; damage-driven streams can be sparse, so
+    // judge on cumulative pushes plus elapsed time, not per-second rate.
     fn check_watchdog(&mut self, consumed: u64) -> bool {
-        if consumed > 0 {
+        let now = Instant::now();
+        let Some(base) = self.watchdog_consumed_base else {
+            self.watchdog_consumed_base = Some(consumed);
+            self.watchdog_since = Some(now);
+            return false;
+        };
+        if consumed > base {
             self.watchdog_armed = false;
             return false;
         }
-        let pushed_in_window = self.pushed_count - self.watchdog_pushed_at_sample;
-        self.watchdog_pushed_at_sample = self.pushed_count;
-        if pushed_in_window >= 10 {
-            self.watchdog_stall_windows += 1;
-        }
-        if self.watchdog_stall_windows >= 3 {
+        if self.pushed_count >= 30
+            && self
+                .watchdog_since
+                .map(|t| now.duration_since(t) >= Duration::from_secs(3))
+                .unwrap_or(false)
+        {
             self.watchdog_armed = false;
             return true;
         }
@@ -342,9 +348,8 @@ impl DisplaySessionInfo {
 }
 
 // Video Texture Renderer in Flutter
-// Each display entry has its own mutex so the per-frame plugin call only ever
-// holds that display's lock; a stalled plugin/driver call must not back up
-// the session-level locks (which would freeze every window's UI thread).
+// Per-display mutexes: the per-frame plugin call must not hold session-level
+// locks, or a stalled plugin/driver call freezes every window's UI thread.
 #[derive(Clone)]
 struct VideoRenderer {
     is_support_multi_ui_session: bool,
@@ -503,11 +508,9 @@ impl VideoRenderer {
         }
     }
 
-    // Clear the pointer only if it still holds `ptr`. An unconditional clear
-    // could wipe out the registration a new window just made while a tab
-    // moves between windows (#8016); skipping the clear (the old behavior on
-    // move) left Rust pushing into a freed native texture. Waiting on the
-    // display mutex also drains an in-flight push through the old pointer.
+    // Compare-and-clear: an unconditional clear could wipe the registration a
+    // new window just made when a tab moves between windows (#8016); waiting
+    // on the display mutex also drains an in-flight push via the old pointer.
     fn unregister_pixelbuffer_texture(&self, display: usize, ptr: usize) {
         if ptr == 0 {
             return;
@@ -622,10 +625,11 @@ impl VideoRenderer {
                         rgba.h
                     );
                 }
-                // The stream is the source of truth; if the sizes still
-                // disagree after this many frames the peer info is not
-                // coming, and dropping forever leaves a live session black.
-                if info.size_mismatch_count < 30 {
+                // If sizes still disagree after this many frames the peer info
+                // is not coming and dropping forever leaves a live session
+                // black. Legacy single-ui-session pairs frames loosely
+                // (values().next()), so only adopt where pairing is exact.
+                if !self.is_support_multi_ui_session || info.size_mismatch_count < 30 {
                     return false;
                 }
                 log::warn!(
@@ -2046,6 +2050,19 @@ pub fn session_unregister_gpu_texture(_session_id: SessionID, _display: usize, _
 // Startup-probe plumbing: the main window pushes one frame into a throwaway
 // 1x1 texture and polls whether the engine consumed it, validating the
 // texture pipeline before any session depends on it.
+#[cfg(not(any(target_os = "android", target_os = "ios")))]
+pub fn texture_render_probe_supported() -> bool {
+    match &*TEXTURE_RGBA_RENDERER_PLUGIN {
+        Ok(lib) => unsafe {
+            lib.symbol::<FlutterRgbaRendererPluginGetConsumed>(
+                "FlutterRgbaRendererPluginGetConsumed",
+            )
+            .is_ok()
+        },
+        Err(_) => false,
+    }
+}
+
 #[cfg(not(any(target_os = "android", target_os = "ios")))]
 pub fn push_texture_probe_frame(ptr: usize) {
     if ptr == 0 {
@@ -2059,7 +2076,8 @@ pub fn push_texture_probe_frame(ptr: usize) {
     }) else {
         return;
     };
-    let frame: [u8; 4] = [255, 255, 255, 255];
+    // Fully transparent so the 1x1 probe pixel is invisible on any theme.
+    let frame: [u8; 4] = [0, 0, 0, 0];
     unsafe { func(ptr as _, frame.as_ptr(), 4, 1, 1, 1) };
 }
 
@@ -2079,12 +2097,15 @@ pub fn get_texture_probe_consumed(ptr: usize) -> u64 {
     unsafe { func(ptr as _) }
 }
 
-// Frames are being pushed but the engine never consumes them: texture
-// rendering does not work in this environment (GPU/driver/engine breakage).
-// Fall back to software rendering for the live session and record it so the
-// default flips to opt-in; the startup probe re-validates on later launches.
+// Frames are being pushed but the engine never consumes them: fall back to
+// software rendering and record the breakage (health flips the default off;
+// a passing startup probe or an explicit option toggle clears it).
 #[cfg(not(any(target_os = "android", target_os = "ios")))]
 fn on_texture_render_failed(session_id: SessionID) {
+    // One record per breakage; later fires (other displays/sessions) no-op.
+    if crate::ui_interface::texture_render_health_failed() {
+        return;
+    }
     log::error!(
         "texture rendering failed for session {}, falling back to software rendering",
         session_id
@@ -2099,12 +2120,30 @@ fn on_texture_render_failed(session_id: SessionID) {
                 .unwrap_or(0)
         ),
     );
-    if let Some(session) = sessions::get_session_by_session_id(&session_id) {
-        session.push_event(
-            "use_texture_render",
-            &[("v", "N"), ("reason", "fallback")],
-            &[],
-        );
+    // Mirror main_set_local_option: every render session must observe the
+    // new effective value, not only the failing one.
+    for session in sessions::get_sessions() {
+        if !(session.is_default() || session.is_view_camera()) {
+            continue;
+        }
+        // The soft path cannot rescue multi-display windows; don't claim it.
+        let fallback_rescues = session
+            .ui_handler
+            .session_handlers
+            .read()
+            .unwrap()
+            .get(&session_id)
+            .map(|h| h.displays.len() <= 1)
+            .unwrap_or(false);
+        if fallback_rescues {
+            session.push_event(
+                "use_texture_render",
+                &[("v", "N"), ("reason", "fallback")],
+                &[],
+            );
+        } else {
+            session.push_event("use_texture_render", &[("v", "N")], &[]);
+        }
         session.use_texture_render_changed();
         session.ui_handler.update_use_texture_render();
     }

src/flutter_ffi.rs

@@ -2322,6 +2322,13 @@ pub fn session_unregister_gpu_texture(
     ))
 }
 
+pub fn main_texture_render_probe_supported() -> SyncReturn<bool> {
+    #[cfg(not(any(target_os = "android", target_os = "ios")))]
+    return SyncReturn(super::flutter::texture_render_probe_supported());
+    #[cfg(any(target_os = "android", target_os = "ios"))]
+    SyncReturn(false)
+}
+
 pub fn main_push_texture_probe_frame(ptr: usize) -> SyncReturn<()> {
     #[cfg(not(any(target_os = "android", target_os = "ios")))]
     super::flutter::push_texture_probe_frame(ptr);

src/ui_interface.rs

@@ -176,10 +176,9 @@ pub fn get_option<T: AsRef<str>>(key: T) -> String {
     }
 }
 
-// The watchdog/startup probe records texture-render breakage (frames pushed
-// but never consumed by the engine). A failed record forces texture render
-// off on every desktop platform — even an explicit "Y" — because the live
-// fallback relies on it; toggling the option (or a passing probe) clears it.
+// Watchdog/probe breakage record: a failure forces texture render off on all
+// desktop platforms (even an explicit "Y") — the live fallback relies on it;
+// toggling the option or a passing probe clears it.
 #[inline]
 #[cfg(not(any(target_os = "android", target_os = "ios")))]
 pub fn texture_render_health_failed() -> bool {