From 103fb78ac1b91874f8b90cc5a165e6f0502179c4 Mon Sep 17 00:00:00 2001
From: Michael Wright <michaelwr@google.com>
Date: Fri, 22 Apr 2016 01:03:09 -0400
Subject: Add ambient light ring buffer for initial data gathering period.

We're seeing reports of the display being too dim at initial wake up.
Saving the buffer for this initial period lets determine whether this
is a calculation error or something wrong with the sensor readings.

Bug: 27951906
Change-Id: I96b5dd0772de056c3c5e54d59c13d1a3d902d343
---
 .../server/display/AutomaticBrightnessController.java  | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/display/AutomaticBrightnessController.java b/services/core/java/com/android/server/display/AutomaticBrightnessController.java
index 5c80d04da10e..c16dac23d4c7 100644
--- a/services/core/java/com/android/server/display/AutomaticBrightnessController.java
+++ b/services/core/java/com/android/server/display/AutomaticBrightnessController.java
@@ -147,6 +147,9 @@ class AutomaticBrightnessController {
     // A ring buffer containing all of the recent ambient light sensor readings.
     private AmbientLightRingBuffer mAmbientLightRingBuffer;
 
+    // A ring buffer containing the light sensor readings for the initial horizon period.
+    private AmbientLightRingBuffer mInitialHorizonAmbientLightRingBuffer;
+
     // The handler
     private AutomaticBrightnessHandler mHandler;
 
@@ -204,7 +207,10 @@ class AutomaticBrightnessController {
         mScreenAutoBrightnessAdjustmentMaxGamma = autoBrightnessAdjustmentMaxGamma;
 
         mHandler = new AutomaticBrightnessHandler(looper);
-        mAmbientLightRingBuffer = new AmbientLightRingBuffer(mLightSensorRate, mAmbientLightHorizon);
+        mAmbientLightRingBuffer =
+            new AmbientLightRingBuffer(mLightSensorRate, mAmbientLightHorizon);
+        mInitialHorizonAmbientLightRingBuffer =
+            new AmbientLightRingBuffer(mLightSensorRate, mAmbientLightHorizon);
 
         if (!DEBUG_PRETEND_LIGHT_SENSOR_ABSENT) {
             mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
@@ -273,6 +279,8 @@ class AutomaticBrightnessController {
         pw.println("  mLastObservedLuxTime=" + TimeUtils.formatUptime(mLastObservedLuxTime));
         pw.println("  mRecentLightSamples=" + mRecentLightSamples);
         pw.println("  mAmbientLightRingBuffer=" + mAmbientLightRingBuffer);
+        pw.println("  mInitialHorizonAmbientLightRingBuffer=" +
+                mInitialHorizonAmbientLightRingBuffer);
         pw.println("  mScreenAutoBrightness=" + mScreenAutoBrightness);
         pw.println("  mScreenAutoBrightnessAdjustment=" + mScreenAutoBrightnessAdjustment);
         pw.println("  mScreenAutoBrightnessAdjustmentMaxGamma=" + mScreenAutoBrightnessAdjustmentMaxGamma);
@@ -295,6 +303,7 @@ class AutomaticBrightnessController {
                 mAmbientLuxValid = !mResetAmbientLuxAfterWarmUpConfig;
                 mRecentLightSamples = 0;
                 mAmbientLightRingBuffer.clear();
+                mInitialHorizonAmbientLightRingBuffer.clear();
                 mHandler.removeMessages(MSG_UPDATE_AMBIENT_LUX);
                 mSensorManager.unregisterListener(mLightSensorListener);
             }
@@ -311,6 +320,11 @@ class AutomaticBrightnessController {
 
     private void applyLightSensorMeasurement(long time, float lux) {
         mRecentLightSamples++;
+        // Store all of the light measurements for the intial horizon period. This is to help
+        // diagnose dim wake ups and slow responses in b/27951906.
+        if (time <= mLightSensorEnableTime + mAmbientLightHorizon) {
+            mInitialHorizonAmbientLightRingBuffer.push(time, lux);
+        }
         mAmbientLightRingBuffer.prune(time - mAmbientLightHorizon);
         mAmbientLightRingBuffer.push(time, lux);
 
@@ -617,7 +631,7 @@ class AutomaticBrightnessController {
         void updateBrightness();
     }
 
-    private static final class AmbientLightRingBuffer{
+    private static final class AmbientLightRingBuffer {
         // Proportional extra capacity of the buffer beyond the expected number of light samples
         // in the horizon
         private static final float BUFFER_SLACK = 1.5f;
-- 
cgit v1.2.3-59-g8ed1b