From fccce26e131ef466739b9a8f39f0e66fe5e4e684 Mon Sep 17 00:00:00 2001
From: Fiona Campbell <flc@google.com>
Date: Wed, 19 Oct 2022 15:58:15 +0000
Subject: [PATCH] Only load default lightsensor for Brightness Tracker

Previously, we were setting new light sensors each time the display
changed. This meant that during transitions between displays, multiple
light sensors could get loaded since we create temporary displays during
transitions. This cl ensures we are only using the light sensor of the
default display, since, for now, BrightnessTracker can only take one
lightsensor.

We also only load the brightness tracker for the default dpc, since
other displays will not use this.

Bug: 248261521
Test: com.android.server.display
Test: dumpsys display | grep -A40 "active connections" and ensure there
is only one instance of a brightness tracker connection.

Change-Id: If0397af675caed0568bed06d82f7d925002c8df8
Merged-In: If0397af675caed0568bed06d82f7d925002c8df8
---
 .../com/android/server/display/DisplayManagerService.java | 2 +-
 .../android/server/display/DisplayPowerController.java    | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/services/core/java/com/android/server/display/DisplayManagerService.java b/services/core/java/com/android/server/display/DisplayManagerService.java
index b153c1ba98e06..a00fadc89973a 100644
--- a/services/core/java/com/android/server/display/DisplayManagerService.java
+++ b/services/core/java/com/android/server/display/DisplayManagerService.java
@@ -2583,7 +2583,7 @@ public final class DisplayManagerService extends SystemService {
             // initPowerManagement has not yet been called.
             return;
         }
-        if (mBrightnessTracker == null) {
+        if (mBrightnessTracker == null && display.getDisplayIdLocked() == Display.DEFAULT_DISPLAY) {
             mBrightnessTracker = new BrightnessTracker(mContext, null);
         }
 
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index efd2e34144666..3e627021b56f7 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -920,7 +920,7 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
 
         // Initialize all of the brightness tracking state
         final float brightness = convertToNits(mPowerState.getScreenBrightness());
-        if (brightness >= PowerManager.BRIGHTNESS_MIN) {
+        if (mBrightnessTracker != null && brightness >= PowerManager.BRIGHTNESS_MIN) {
             mBrightnessTracker.start(brightness);
         }
         mBrightnessSettingListener = brightnessValue -> {
@@ -1026,7 +1026,9 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
             }
 
             loadAmbientLightSensor();
-            if (mBrightnessTracker != null) {
+            // BrightnessTracker should only use one light sensor, we want to use the light sensor
+            // from the default display and not e.g. temporary displays when switching layouts.
+            if (mBrightnessTracker != null && mDisplayId == Display.DEFAULT_DISPLAY) {
                 mBrightnessTracker.setLightSensor(mLightSensor);
             }
 
@@ -2434,7 +2436,7 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
             boolean hadUserDataPoint) {
         final float brightnessInNits = convertToNits(brightness);
         if (mPowerRequest.useAutoBrightness && brightnessInNits >= 0.0f
-                && mAutomaticBrightnessController != null) {
+                && mAutomaticBrightnessController != null && mBrightnessTracker != null) {
             // We only want to track changes on devices that can actually map the display backlight
             // values into a physical brightness unit since the value provided by the API is in
             // nits and not using the arbitrary backlight units.