From 0d192a9e279133f80a288d34e50c64a5c91c1a5b Mon Sep 17 00:00:00 2001
From: Dianne Hackborn <hackbod@google.com>
Date: Tue, 15 Jul 2014 16:39:47 -0700
Subject: [PATCH] Maybe fix issue #16167054: Wakelock is acquired and released
 in...

...battery history even though CPU is in suspend

There is a race in the power manager between noting a wake lock
acquire and ensuring the device is staying awake.

Change-Id: I3d76f99d73dca119b09f253f0e31448408c88a3c
---
 .../android/server/power/PowerManagerService.java    | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/services/core/java/com/android/server/power/PowerManagerService.java b/services/core/java/com/android/server/power/PowerManagerService.java
index ebad4224199af..cb4d3399de9ad 100644
--- a/services/core/java/com/android/server/power/PowerManagerService.java
+++ b/services/core/java/com/android/server/power/PowerManagerService.java
@@ -698,6 +698,7 @@ public final class PowerManagerService extends com.android.server.SystemService
 
             WakeLock wakeLock;
             int index = findWakeLockIndexLocked(lock);
+            boolean notifyAcquire;
             if (index >= 0) {
                 wakeLock = mWakeLocks.get(index);
                 if (!wakeLock.hasSameProperties(flags, tag, ws, uid, pid)) {
@@ -706,6 +707,7 @@ public final class PowerManagerService extends com.android.server.SystemService
                             uid, pid, ws, historyTag);
                     wakeLock.updateProperties(flags, tag, packageName, ws, historyTag, uid, pid);
                 }
+                notifyAcquire = false;
             } else {
                 wakeLock = new WakeLock(lock, flags, tag, packageName, ws, historyTag, uid, pid);
                 try {
@@ -713,13 +715,21 @@ public final class PowerManagerService extends com.android.server.SystemService
                 } catch (RemoteException ex) {
                     throw new IllegalArgumentException("Wake lock is already dead.");
                 }
-                notifyWakeLockAcquiredLocked(wakeLock);
                 mWakeLocks.add(wakeLock);
+                notifyAcquire = true;
             }
 
             applyWakeLockFlagsOnAcquireLocked(wakeLock);
             mDirty |= DIRTY_WAKE_LOCKS;
             updatePowerStateLocked();
+            if (notifyAcquire) {
+                // This needs to be done last so we are sure we have acquired the
+                // kernel wake lock.  Otherwise we have a race where the system may
+                // go to sleep between the time we start the accounting in battery
+                // stats and when we actually get around to telling the kernel to
+                // stay awake.
+                notifyWakeLockAcquiredLocked(wakeLock);
+            }
         }
     }