Merge "Apply rotation change on display thread" into udc-qpr-dev

services/core/java/com/android/server/wm/Transition.java

@@ -77,6 +77,7 @@ import android.os.Binder;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.os.IRemoteCallback;
+import android.os.Looper;
 import android.os.RemoteException;
 import android.os.SystemClock;
 import android.os.Trace;
@@ -2696,6 +2697,26 @@ class Transition implements BLASTSyncEngine.TransactionReadyListener {
         });
     }
 
+    /**
+     * Returns {@code true} if the transition and the corresponding transaction should be applied
+     * on display thread. Currently, this only checks for display rotation change because the order
+     * of dispatching the new display info will be after requesting the windows to sync drawing.
+     * That avoids potential flickering of screen overlays (e.g. cutout, rounded corner). Also,
+     * because the display thread has a higher priority, it is faster to perform the configuration
+     * changes and window hierarchy traversal.
+     */
+    boolean shouldApplyOnDisplayThread() {
+        for (int i = mParticipants.size() - 1; i >= 0; --i) {
+            final DisplayContent dc = mParticipants.valueAt(i).asDisplayContent();
+            if (dc == null) continue;
+            final ChangeInfo changeInfo = mChanges.get(dc);
+            if (changeInfo != null && changeInfo.mRotation != dc.getRotation()) {
+                return Looper.myLooper() != mController.mAtm.mWindowManager.mH.getLooper();
+            }
+        }
+        return false;
+    }
+
     /** Applies the new configuration for the changed displays. */
     void applyDisplayChangeIfNeeded() {
         for (int i = mParticipants.size() - 1; i >= 0; --i) {

services/core/java/com/android/server/wm/TransitionController.java

@@ -588,15 +588,6 @@ class TransitionController {
     /** Sets the sync method for the display change. */
     private void setDisplaySyncMethod(@NonNull TransitionRequestInfo.DisplayChange displayChange,
             @NonNull Transition displayTransition, @NonNull DisplayContent displayContent) {
-        final int startRotation = displayChange.getStartRotation();
-        final int endRotation = displayChange.getEndRotation();
-        if (startRotation != endRotation && (startRotation + endRotation) % 2 == 0) {
-            // 180 degrees rotation change may not change screen size. So the clients may draw
-            // some frames before and after the display projection transaction is applied by the
-            // remote player. That may cause some buffers to show in different rotation. So use
-            // sync method to pause clients drawing until the projection transaction is applied.
-            mSyncEngine.setSyncMethod(displayTransition.getSyncId(), BLASTSyncEngine.METHOD_BLAST);
-        }
         final Rect startBounds = displayChange.getStartAbsBounds();
         final Rect endBounds = displayChange.getEndAbsBounds();
         if (startBounds == null || endBounds == null) return;

services/core/java/com/android/server/wm/WindowOrganizerController.java

@@ -321,9 +321,18 @@ class WindowOrganizerController extends IWindowOrganizerController.Stub
                     applyTransaction(wct, -1 /*syncId*/, null /*transition*/, caller);
                     return transition.getToken();
                 }
-                transition.start();
                 transition.mLogger.mStartWCT = wct;
-                applyTransaction(wct, -1 /*syncId*/, transition, caller);
+                if (transition.shouldApplyOnDisplayThread()) {
+                    mService.mH.post(() -> {
+                        synchronized (mService.mGlobalLock) {
+                            transition.start();
+                            applyTransaction(wct, -1 /* syncId */, transition, caller);
+                        }
+                    });
+                } else {
+                    transition.start();
+                    applyTransaction(wct, -1 /* syncId */, transition, caller);
+                }
                 // Since the transition is already provided, it means WMCore is determining the
                 // "readiness lifecycle" outside the provided transaction, so don't set ready here.
                 return transition.getToken();

services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java

@@ -2046,6 +2046,7 @@ public class DisplayContentTests extends WindowTestsBase {
 
         // Once transition starts, rotation is applied and transition shows DC rotating.
         testPlayer.startTransition();
+        waitUntilHandlersIdle();
         assertNotEquals(origRot, dc.getConfiguration().windowConfiguration.getRotation());
         assertNotNull(testPlayer.mLastReady);
         assertTrue(testPlayer.mController.isPlaying());