From 1beb4fcdbd1e82ba934ebcfacee626d7c16133ec Mon Sep 17 00:00:00 2001
From: Dmitri Plotnikov <dplotnikov@google.com>
Date: Mon, 21 Jun 2021 17:18:38 -0700
Subject: [PATCH] Fix Bluetooth power accounting after a BT crash

Bug: 191488536
Test: Use BatteryStatsViewer to take a note of BT usage time
      $ adb shell killall com.android.bluetooth
      Use BatteryStatsViewer to verify that BT usage time is going up
Change-Id: I8438f19bb4bd6365da6d582fb7347f0a2cbddc1c
---
 .../android/internal/os/BatteryStatsImpl.java  | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index 945a6ab118565..dab3e9fa15fa8 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -12141,6 +12141,15 @@ public class BatteryStatsImpl extends BatteryStats {
                 }
             }
         }
+
+        void reset() {
+            idleTimeMs = 0;
+            rxTimeMs = 0;
+            txTimeMs = 0;
+            energy = 0;
+            uidRxBytes.clear();
+            uidTxBytes.clear();
+        }
     }
 
     private final BluetoothActivityInfoCache mLastBluetoothActivityInfo
@@ -12167,6 +12176,15 @@ public class BatteryStatsImpl extends BatteryStats {
 
         mHasBluetoothReporting = true;
 
+        if (info.getControllerRxTimeMillis() < mLastBluetoothActivityInfo.rxTimeMs
+                || info.getControllerTxTimeMillis() < mLastBluetoothActivityInfo.txTimeMs
+                || info.getControllerIdleTimeMillis() < mLastBluetoothActivityInfo.idleTimeMs
+                || info.getControllerEnergyUsed() < mLastBluetoothActivityInfo.energy) {
+            // A drop in accumulated Bluetooth stats is a sign of a Bluetooth crash.
+            // Reset the preserved previous snapshot in order to restart accumulating deltas.
+            mLastBluetoothActivityInfo.reset();
+        }
+
         final long rxTimeMs =
                 info.getControllerRxTimeMillis() - mLastBluetoothActivityInfo.rxTimeMs;
         final long txTimeMs =