From c55dbcd4ecc8c97ee8c4da9e355561f2f5582d6c Mon Sep 17 00:00:00 2001
From: Riddle Hsu <riddlehsu@google.com>
Date: Mon, 10 Apr 2023 23:53:25 +0800
Subject: [PATCH] Use blast sync only for overlay decor when resizing display

Only the windows above the screenshot need to be synced.
This avoids requesting several windows in the same process
to sync at the same time, which may occupy buffers and
block RenderThread.

Bug: 277214890
Test: CompatChangeTests
Test: Loop "wm size 800x1600" and "wm size reset".
      SystemUI still works normally.

Change-Id: I611586ee2edea1dfca3e9b59497fe3e76395589f
---
 .../server/wm/TransitionController.java       | 30 ++++++++++++-------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/services/core/java/com/android/server/wm/TransitionController.java b/services/core/java/com/android/server/wm/TransitionController.java
index 3bf896939f49a..742ab7cec9ff0 100644
--- a/services/core/java/com/android/server/wm/TransitionController.java
+++ b/services/core/java/com/android/server/wm/TransitionController.java
@@ -443,26 +443,36 @@ class TransitionController {
         return type == TRANSIT_OPEN || type == TRANSIT_CLOSE;
     }
 
-    /** Whether the display change should run with blast sync. */
-    private static boolean shouldSync(@NonNull TransitionRequestInfo.DisplayChange displayChange) {
-        if ((displayChange.getStartRotation() + displayChange.getEndRotation()) % 2 == 0) {
+    /** 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.
-            return true;
+            mAtm.mWindowManager.mSyncEngine.setSyncMethod(displayTransition.getSyncId(),
+                    BLASTSyncEngine.METHOD_BLAST);
         }
         final Rect startBounds = displayChange.getStartAbsBounds();
         final Rect endBounds = displayChange.getEndAbsBounds();
-        if (startBounds == null || endBounds == null) return false;
+        if (startBounds == null || endBounds == null) return;
         final int startWidth = startBounds.width();
         final int startHeight = startBounds.height();
         final int endWidth = endBounds.width();
         final int endHeight = endBounds.height();
         // This is changing screen resolution. Because the screen decor layers are excluded from
         // screenshot, their draw transactions need to run with the start transaction.
-        return (endWidth > startWidth) == (endHeight > startHeight)
-                && (endWidth != startWidth || endHeight != startHeight);
+        if ((endWidth > startWidth) == (endHeight > startHeight)
+                && (endWidth != startWidth || endHeight != startHeight)) {
+            displayContent.forAllWindows(w -> {
+                if (w.mToken.mRoundedCornerOverlay && w.mHasSurface) {
+                    w.mSyncMethodOverride = BLASTSyncEngine.METHOD_BLAST;
+                }
+            }, true /* traverseTopToBottom */);
+        }
     }
 
     /**
@@ -494,9 +504,9 @@ class TransitionController {
         } else {
             newTransition = requestStartTransition(createTransition(type, flags),
                     trigger != null ? trigger.asTask() : null, remoteTransition, displayChange);
-            if (newTransition != null && displayChange != null && shouldSync(displayChange)) {
-                mAtm.mWindowManager.mSyncEngine.setSyncMethod(newTransition.getSyncId(),
-                        BLASTSyncEngine.METHOD_BLAST);
+            if (newTransition != null && displayChange != null && trigger != null
+                    && trigger.asDisplayContent() != null) {
+                setDisplaySyncMethod(displayChange, newTransition, trigger.asDisplayContent());
             }
         }
         if (trigger != null) {