diff --git a/core/java/android/view/IWindowSession.aidl b/core/java/android/view/IWindowSession.aidl
index 990b7bdfa9873..dad932c2ee199 100644
--- a/core/java/android/view/IWindowSession.aidl
+++ b/core/java/android/view/IWindowSession.aidl
@@ -122,14 +122,6 @@ interface IWindowSession {
      */
     boolean outOfMemory(IWindow window);
 
-    /**
-     * Give the window manager a hint of the part of the window that is
-     * completely transparent, allowing it to work with the surface flinger
-     * to optimize compositing of this part of the window.
-     */
-    @UnsupportedAppUsage
-    oneway void setTransparentRegion(IWindow window, in Region region);
-
     /**
      * Tell the window manager about the content and visible insets of the
      * given window, which can be used to adjust the <var>outContentInsets</var>
diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index acc77b5412938..4716141ee8d30 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -3064,11 +3064,14 @@ public final class ViewRootImpl implements ViewParent,
                 if (!mTransparentRegion.equals(mPreviousTransparentRegion)) {
                     mPreviousTransparentRegion.set(mTransparentRegion);
                     mFullRedrawNeeded = true;
-                    // reconfigure window manager
-                    try {
-                        mWindowSession.setTransparentRegion(mWindow, mTransparentRegion);
-                    } catch (RemoteException e) {
-                    }
+                    // TODO: Ideally we would do this in prepareSurfaces,
+                    // but prepareSurfaces is currently working under
+                    // the assumption that we paused the render thread
+                    // via the WM relayout code path. We probably eventually
+                    // want to synchronize transparent region hint changes
+                    // with draws.
+                    mTransaction.setTransparentRegionHint(getSurfaceControl(),
+                        mTransparentRegion).apply();
                 }
             }
 
diff --git a/core/java/android/view/WindowlessWindowManager.java b/core/java/android/view/WindowlessWindowManager.java
index 3aedda1a6bd3f..39d3c01dd409c 100644
--- a/core/java/android/view/WindowlessWindowManager.java
+++ b/core/java/android/view/WindowlessWindowManager.java
@@ -313,10 +313,6 @@ public class WindowlessWindowManager implements IWindowSession {
         return false;
     }
 
-    @Override
-    public void setTransparentRegion(android.view.IWindow window, android.graphics.Region region) {
-    }
-
     @Override
     public void setInsets(android.view.IWindow window, int touchableInsets,
             android.graphics.Rect contentInsets, android.graphics.Rect visibleInsets,
diff --git a/services/core/java/com/android/server/wm/Session.java b/services/core/java/com/android/server/wm/Session.java
index 37bb2740f3f0f..8b186796db8d0 100644
--- a/services/core/java/com/android/server/wm/Session.java
+++ b/services/core/java/com/android/server/wm/Session.java
@@ -247,11 +247,6 @@ class Session extends IWindowSession.Stub implements IBinder.DeathRecipient {
         return mService.outOfMemoryWindow(this, window);
     }
 
-    @Override
-    public void setTransparentRegion(IWindow window, Region region) {
-        mService.setTransparentRegionWindow(this, window, region);
-    }
-
     @Override
     public void setInsets(IWindow window, int touchableInsets,
             Rect contentInsets, Rect visibleInsets, Region touchableArea) {
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 3c7bab3da2794..23487252c91c8 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -2150,23 +2150,6 @@ public class WindowManagerService extends IWindowManager.Stub
         Slog.i(tag, s, e);
     }
 
-    void setTransparentRegionWindow(Session session, IWindow client, Region region) {
-        final long origId = Binder.clearCallingIdentity();
-        try {
-            synchronized (mGlobalLock) {
-                WindowState w = windowForClientLocked(session, client, false);
-                ProtoLog.i(WM_SHOW_TRANSACTIONS, "SURFACE transparentRegionHint=%s: %s",
-                        region, w);
-
-                if ((w != null) && w.mHasSurface) {
-                    w.mWinAnimator.setTransparentRegionHintLocked(region);
-                }
-            }
-        } finally {
-            Binder.restoreCallingIdentity(origId);
-        }
-    }
-
     void setInsetsWindow(Session session, IWindow client, int touchableInsets, Rect contentInsets,
             Rect visibleInsets, Region touchableRegion) {
         int uid = Binder.getCallingUid();
diff --git a/services/core/java/com/android/server/wm/WindowStateAnimator.java b/services/core/java/com/android/server/wm/WindowStateAnimator.java
index fe70dc12d3a2d..ece256e8c591b 100644
--- a/services/core/java/com/android/server/wm/WindowStateAnimator.java
+++ b/services/core/java/com/android/server/wm/WindowStateAnimator.java
@@ -678,14 +678,6 @@ class WindowStateAnimator {
         }
     }
 
-    void setTransparentRegionHintLocked(final Region region) {
-        if (mSurfaceController == null) {
-            Slog.w(TAG, "setTransparentRegionHint: null mSurface after mHasSurface true");
-            return;
-        }
-        mSurfaceController.setTransparentRegionHint(region);
-    }
-
     boolean setWallpaperOffset(int dx, int dy, float scale) {
         if (mXOffset == dx && mYOffset == dy && Float.compare(mWallpaperScale, scale) == 0) {
             return false;
diff --git a/services/core/java/com/android/server/wm/WindowSurfaceController.java b/services/core/java/com/android/server/wm/WindowSurfaceController.java
index 82ba3c188b76e..636f0bb6086fe 100644
--- a/services/core/java/com/android/server/wm/WindowSurfaceController.java
+++ b/services/core/java/com/android/server/wm/WindowSurfaceController.java
@@ -194,22 +194,6 @@ class WindowSurfaceController {
         return true;
     }
 
-    void setTransparentRegionHint(final Region region) {
-        if (mSurfaceControl == null) {
-            Slog.w(TAG, "setTransparentRegionHint: null mSurface after mHasSurface true");
-            return;
-        }
-        if (SHOW_LIGHT_TRANSACTIONS) Slog.i(TAG, ">>> OPEN TRANSACTION setTransparentRegion");
-        mService.openSurfaceTransaction();
-        try {
-            getGlobalTransaction().setTransparentRegionHint(mSurfaceControl, region);
-        } finally {
-            mService.closeSurfaceTransaction("setTransparentRegion");
-            if (SHOW_LIGHT_TRANSACTIONS) Slog.i(TAG,
-                    "<<< CLOSE TRANSACTION setTransparentRegion");
-        }
-    }
-
     void setOpaque(boolean isOpaque) {
         ProtoLog.i(WM_SHOW_TRANSACTIONS, "SURFACE isOpaque=%b: %s", isOpaque, title);