From 8b37bc0a8353bb11a6cae6c5e8c7fc19cbe91c21 Mon Sep 17 00:00:00 2001
From: Riddle Hsu <riddlehsu@google.com>
Date: Sat, 23 Nov 2019 00:39:14 +0800
Subject: [PATCH] Move blocking surface operations out of lock

SurfaceFlinger may take a while when toggling display power mode.
The caller who uses the other sync methods of SurfaceControl at
this time will also be blocked.

Because these procedures may be called during traversal, that may
affect the speed of unlocking.

DisplayManagerService:
 performTraversalLocked -> configureDisplayLocked
 -> LocalDisplay: configureDisplayLocked
    -> LocalDisplayAdapter.LocalDisplayDevice:
        setDesiredDisplayModeSpecsLocked
        setRequestedColorModeLocked

Bug: 143234343
Test: 1. Add trace around
         DisplayManagerService#performTraversalInternal
         and SurfaceControl#setDisplayPowerMode.
      2. Remove check of mode change (force always update).
      3. Turn on/off screen and check the trace that
         animation thread should not be blocked by a
         binder transaction to SurfaceFlinger.

Change-Id: Icd916d6c7b4e3fda485f41ca8b3da56521e12a06
---
 .../server/display/LocalDisplayAdapter.java   | 44 ++++++++++++++-----
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/services/core/java/com/android/server/display/LocalDisplayAdapter.java b/services/core/java/com/android/server/display/LocalDisplayAdapter.java
index eebc738ca26ac..cf94d46954978 100644
--- a/services/core/java/com/android/server/display/LocalDisplayAdapter.java
+++ b/services/core/java/com/android/server/display/LocalDisplayAdapter.java
@@ -37,6 +37,7 @@ import android.view.DisplayEventReceiver;
 import android.view.Surface;
 import android.view.SurfaceControl;
 
+import com.android.internal.util.function.pooled.PooledLambda;
 import com.android.server.LocalServices;
 import com.android.server.lights.Light;
 import com.android.server.lights.LightsManager;
@@ -641,9 +642,7 @@ final class LocalDisplayAdapter extends DisplayAdapter {
 
         @Override
         public void setRequestedColorModeLocked(int colorMode) {
-            if (requestColorModeLocked(colorMode)) {
-                updateDeviceInfoLocked();
-            }
+            requestColorModeLocked(colorMode);
         }
 
         @Override
@@ -671,12 +670,22 @@ final class LocalDisplayAdapter extends DisplayAdapter {
             if (mDisplayModeSpecsInvalid || !displayModeSpecs.equals(mDisplayModeSpecs)) {
                 mDisplayModeSpecsInvalid = false;
                 mDisplayModeSpecs.copyFrom(displayModeSpecs);
-                final IBinder token = getDisplayTokenLocked();
-                SurfaceControl.setDesiredDisplayConfigSpecs(token,
+                getHandler().sendMessage(PooledLambda.obtainMessage(
+                        LocalDisplayDevice::setDesiredDisplayModeSpecsAsync, this,
+                        getDisplayTokenLocked(),
                         new SurfaceControl.DesiredDisplayConfigSpecs(defaultPhysIndex,
                                 mDisplayModeSpecs.refreshRateRange.min,
-                                mDisplayModeSpecs.refreshRateRange.max));
-                int activePhysIndex = SurfaceControl.getActiveConfig(token);
+                                mDisplayModeSpecs.refreshRateRange.max)));
+            }
+        }
+
+        private void setDesiredDisplayModeSpecsAsync(IBinder displayToken,
+                SurfaceControl.DesiredDisplayConfigSpecs configSpecs) {
+            // Do not lock when calling these SurfaceControl methods because they are sync
+            // operations that may block for a while when setting display power mode.
+            SurfaceControl.setDesiredDisplayConfigSpecs(displayToken, configSpecs);
+            final int activePhysIndex = SurfaceControl.getActiveConfig(displayToken);
+            synchronized (getSyncRoot()) {
                 if (updateActiveModeLocked(activePhysIndex)) {
                     updateDeviceInfoLocked();
                 }
@@ -708,19 +717,30 @@ final class LocalDisplayAdapter extends DisplayAdapter {
             return true;
         }
 
-        public boolean requestColorModeLocked(int colorMode) {
+        public void requestColorModeLocked(int colorMode) {
             if (mActiveColorMode == colorMode) {
-                return false;
+                return;
             }
             if (!mSupportedColorModes.contains(colorMode)) {
                 Slog.w(TAG, "Unable to find color mode " + colorMode
                         + ", ignoring request.");
-                return false;
+                return;
             }
-            SurfaceControl.setActiveColorMode(getDisplayTokenLocked(), colorMode);
+
             mActiveColorMode = colorMode;
             mActiveColorModeInvalid = false;
-            return true;
+            getHandler().sendMessage(PooledLambda.obtainMessage(
+                    LocalDisplayDevice::requestColorModeAsync, this,
+                    getDisplayTokenLocked(), colorMode));
+        }
+
+        private void requestColorModeAsync(IBinder displayToken, int colorMode) {
+            // Do not lock when calling this SurfaceControl method because it is a sync operation
+            // that may block for a while when setting display power mode.
+            SurfaceControl.setActiveColorMode(displayToken, colorMode);
+            synchronized (getSyncRoot()) {
+                updateDeviceInfoLocked();
+            }
         }
 
         @Override