server/power/PowerManagerService.java

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.server.power;

import com.android.internal.app.IBatteryStats;
import com.android.server.BatteryService;
import com.android.server.EventLogTags;
import com.android.server.LightsService;
import com.android.server.TwilightService;
import com.android.server.Watchdog;
import com.android.server.am.ActivityManagerService;
import com.android.server.display.DisplayManagerService;
import com.android.server.dreams.DreamManagerService;

import android.Manifest;
import android.content.BroadcastReceiver;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.BatteryManager;
import android.os.Binder;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.IPowerManager;
import android.os.Looper;
import android.os.Message;
import android.os.PowerManager;
import android.os.Process;
import android.os.RemoteException;
import android.os.SystemClock;
import android.os.UserHandle;
import android.os.WorkSource;
import android.provider.Settings;
import android.util.EventLog;
import android.util.Log;
import android.util.Slog;
import android.util.TimeUtils;
import android.view.WindowManagerPolicy;

import java.io.FileDescriptor;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;

import libcore.util.Objects;

/**
 * The power manager service is responsible for coordinating power management
 * functions on the device.
 */
public final class PowerManagerService extends IPowerManager.Stub
        implements Watchdog.Monitor {
    private static final String TAG = "PowerManagerService";

    private static final boolean DEBUG = false;
    private static final boolean DEBUG_SPEW = DEBUG && true;

    // Message: Sent when a user activity timeout occurs to update the power state.
    private static final int MSG_USER_ACTIVITY_TIMEOUT = 1;
    // Message: Sent when the device enters or exits a napping or dreaming state.
    private static final int MSG_SANDMAN = 2;

    // Dirty bit: mWakeLocks changed
    private static final int DIRTY_WAKE_LOCKS = 1 << 0;
    // Dirty bit: mWakefulness changed
    private static final int DIRTY_WAKEFULNESS = 1 << 1;
    // Dirty bit: user activity was poked or may have timed out
    private static final int DIRTY_USER_ACTIVITY = 1 << 2;
    // Dirty bit: actual display power state was updated asynchronously
    private static final int DIRTY_ACTUAL_DISPLAY_POWER_STATE_UPDATED = 1 << 3;
    // Dirty bit: mBootCompleted changed
    private static final int DIRTY_BOOT_COMPLETED = 1 << 4;
    // Dirty bit: settings changed
    private static final int DIRTY_SETTINGS = 1 << 5;
    // Dirty bit: mIsPowered changed
    private static final int DIRTY_IS_POWERED = 1 << 6;
    // Dirty bit: mStayOn changed
    private static final int DIRTY_STAY_ON = 1 << 7;
    // Dirty bit: battery state changed
    private static final int DIRTY_BATTERY_STATE = 1 << 8;

    // Wakefulness: The device is asleep and can only be awoken by a call to wakeUp().
    // The screen should be off or in the process of being turned off by the display controller.
    private static final int WAKEFULNESS_ASLEEP = 0;
    // Wakefulness: The device is fully awake.  It can be put to sleep by a call to goToSleep().
    // When the user activity timeout expires, the device may start napping or go to sleep.
    private static final int WAKEFULNESS_AWAKE = 1;
    // Wakefulness: The device is napping.  It is deciding whether to dream or go to sleep
    // but hasn't gotten around to it yet.  It can be awoken by a call to wakeUp(), which
    // ends the nap. User activity may brighten the screen but does not end the nap.
    private static final int WAKEFULNESS_NAPPING = 2;
    // Wakefulness: The device is dreaming.  It can be awoken by a call to wakeUp(),
    // which ends the dream.  The device goes to sleep when goToSleep() is called, when
    // the dream ends or when unplugged.
    // User activity may brighten the screen but does not end the dream.
    private static final int WAKEFULNESS_DREAMING = 3;

    // Summarizes the state of all active wakelocks.
    private static final int WAKE_LOCK_CPU = 1 << 0;
    private static final int WAKE_LOCK_SCREEN_BRIGHT = 1 << 1;
    private static final int WAKE_LOCK_SCREEN_DIM = 1 << 2;
    private static final int WAKE_LOCK_BUTTON_BRIGHT = 1 << 3;
    private static final int WAKE_LOCK_PROXIMITY_SCREEN_OFF = 1 << 4;

    // Summarizes the user activity state.
    private static final int USER_ACTIVITY_SCREEN_BRIGHT = 1 << 0;
    private static final int USER_ACTIVITY_SCREEN_DIM = 1 << 1;

    // Default and minimum screen off timeout in milliseconds.
    private static final int DEFAULT_SCREEN_OFF_TIMEOUT = 15 * 1000;
    private static final int MINIMUM_SCREEN_OFF_TIMEOUT = 10 * 1000;

    // The screen dim duration, in milliseconds.
    // This is subtracted from the end of the screen off timeout so the
    // minimum screen off timeout should be longer than this.
    private static final int SCREEN_DIM_DURATION = 7 * 1000;

    // The maximum screen dim time expressed as a ratio relative to the screen
    // off timeout.  If the screen off timeout is very short then we want the
    // dim timeout to also be quite short so that most of the time is spent on.
    // Otherwise the user won't get much screen on time before dimming occurs.
    private static final float MAXIMUM_SCREEN_DIM_RATIO = 0.2f;

    // Upper bound on the battery charge percentage in order to consider turning
    // the screen on when the device starts charging wirelessly.
    // See point of use for more details.
    private static final int WIRELESS_CHARGER_TURN_ON_BATTERY_LEVEL_LIMIT = 95;

    private Context mContext;
    private LightsService mLightsService;
    private BatteryService mBatteryService;
    private IBatteryStats mBatteryStats;
    private HandlerThread mHandlerThread;
    private PowerManagerHandler mHandler;
    private WindowManagerPolicy mPolicy;
    private Notifier mNotifier;
    private DisplayPowerController mDisplayPowerController;
    private SettingsObserver mSettingsObserver;
    private DreamManagerService mDreamManager;
    private LightsService.Light mAttentionLight;

    private final Object mLock = new Object();

    // A bitfield that indicates what parts of the power state have
    // changed and need to be recalculated.
    private int mDirty;

    // Indicates whether the device is awake or asleep or somewhere in between.
    // This is distinct from the screen power state, which is managed separately.
    private int mWakefulness;

    // True if MSG_SANDMAN has been scheduled.
    private boolean mSandmanScheduled;

    // Table of all suspend blockers.
    // There should only be a few of these.
    private final ArrayList<SuspendBlocker> mSuspendBlockers = new ArrayList<SuspendBlocker>();

    // Table of all wake locks acquired by applications.
    private final ArrayList<WakeLock> mWakeLocks = new ArrayList<WakeLock>();

    // A bitfield that summarizes the state of all active wakelocks.
    private int mWakeLockSummary;

    // If true, instructs the display controller to wait for the proximity sensor to
    // go negative before turning the screen on.
    private boolean mRequestWaitForNegativeProximity;

    // Timestamp of the last time the device was awoken or put to sleep.
    private long mLastWakeTime;
    private long mLastSleepTime;

    // True if we need to send a wake up or go to sleep finished notification
    // when the display is ready.
    private boolean mSendWakeUpFinishedNotificationWhenReady;
    private boolean mSendGoToSleepFinishedNotificationWhenReady;

    // Timestamp of the last call to user activity.
    private long mLastUserActivityTime;
    private long mLastUserActivityTimeNoChangeLights;

    // A bitfield that summarizes the effect of the user activity timer.
    // A zero value indicates that the user activity timer has expired.
    private int mUserActivitySummary;

    // The desired display power state.  The actual state may lag behind the
    // requested because it is updated asynchronously by the display power controller.
    private final DisplayPowerRequest mDisplayPowerRequest = new DisplayPowerRequest();

    // The time the screen was last turned off, in elapsedRealtime() timebase.
    private long mLastScreenOffEventElapsedRealTime;

    // True if the display power state has been fully applied, which means the display
    // is actually on or actually off or whatever was requested.
    private boolean mDisplayReady;

    // True if holding a wake-lock to block suspend of the CPU.
    private boolean mHoldingWakeLockSuspendBlocker;

    // The suspend blocker used to keep the CPU alive when wake locks have been acquired.
    private final SuspendBlocker mWakeLockSuspendBlocker;

    // True if systemReady() has been called.
    private boolean mSystemReady;

    // True if boot completed occurred.  We keep the screen on until this happens.
    private boolean mBootCompleted;

    // True if the device is plugged into a power source.
    private boolean mIsPowered;

    // The current plug type, such as BatteryManager.BATTERY_PLUGGED_WIRELESS.
    private int mPlugType;

    // True if the device should wake up when plugged or unplugged.
    private boolean mWakeUpWhenPluggedOrUnpluggedConfig;

    // True if dreams are supported on this device.
    private boolean mDreamsSupportedConfig;

    // True if dreams are enabled by the user.
    private boolean mDreamsEnabledSetting;

    // True if dreams should be activated on sleep.
    private boolean mDreamsActivateOnSleepSetting;

    // The screen off timeout setting value in milliseconds.
    private int mScreenOffTimeoutSetting;

    // The maximum allowable screen off timeout according to the device
    // administration policy.  Overrides other settings.
    private int mMaximumScreenOffTimeoutFromDeviceAdmin = Integer.MAX_VALUE;

    // The stay on while plugged in setting.
    // A bitfield of battery conditions under which to make the screen stay on.
    private int mStayOnWhilePluggedInSetting;

    // True if the device should stay on.
    private boolean mStayOn;

    // Screen brightness setting limits.
    private int mScreenBrightnessSettingMinimum;
    private int mScreenBrightnessSettingMaximum;
    private int mScreenBrightnessSettingDefault;

    // The screen brightness setting, from 0 to 255.
    // Use -1 if no value has been set.
    private int mScreenBrightnessSetting;

    // The screen auto-brightness adjustment setting, from -1 to 1.
    // Use 0 if there is no adjustment.
    private float mScreenAutoBrightnessAdjustmentSetting;

    // The screen brightness mode.
    // One of the Settings.System.SCREEN_BRIGHTNESS_MODE_* constants.
    private int mScreenBrightnessModeSetting;

    // The screen brightness setting override from the window manager
    // to allow the current foreground activity to override the brightness.
    // Use -1 to disable.
    private int mScreenBrightnessOverrideFromWindowManager = -1;

    // The user activity timeout override from the window manager
    // to allow the current foreground activity to override the user activity timeout.
    // Use -1 to disable.
    private long mUserActivityTimeoutOverrideFromWindowManager = -1;

    // The screen brightness setting override from the settings application
    // to temporarily adjust the brightness until next updated,
    // Use -1 to disable.
    private int mTemporaryScreenBrightnessSettingOverride = -1;

    // The screen brightness adjustment setting override from the settings
    // application to temporarily adjust the auto-brightness adjustment factor
    // until next updated, in the range -1..1.
    // Use NaN to disable.
    private float mTemporaryScreenAutoBrightnessAdjustmentSettingOverride = Float.NaN;

    // Time when we last logged a warning about calling userActivity() without permission.
    private long mLastWarningAboutUserActivityPermission = Long.MIN_VALUE;

    private native void nativeInit();
    private static native void nativeShutdown();
    private static native void nativeReboot(String reason) throws IOException;

    private static native void nativeSetPowerState(boolean screenOn, boolean screenBright);
    private static native void nativeAcquireSuspendBlocker(String name);
    private static native void nativeReleaseSuspendBlocker(String name);

    static native void nativeSetScreenState(boolean on);

    public PowerManagerService() {
        synchronized (mLock) {
            mWakeLockSuspendBlocker = createSuspendBlockerLocked("PowerManagerService");
            mWakeLockSuspendBlocker.acquire();
            mHoldingWakeLockSuspendBlocker = true;
            mWakefulness = WAKEFULNESS_AWAKE;
        }

        nativeInit();
        nativeSetPowerState(true, true);
    }

    /**
     * Initialize the power manager.
     * Must be called before any other functions within the power manager are called.
     */
    public void init(Context context, LightsService ls,
            ActivityManagerService am, BatteryService bs, IBatteryStats bss,
            DisplayManagerService dm) {
        // Forcibly turn the screen on at boot so that it is in a known power state.
        // We do this in init() rather than in the constructor because setting the
        // screen state requires a call into surface flinger which then needs to call back
        // into the activity manager to check permissions.  Unfortunately the
        // activity manager is not running when the constructor is called, so we
        // have to defer setting the screen state until this point.
        nativeSetScreenState(true);

        mContext = context;
        mLightsService = ls;
        mBatteryService = bs;
        mBatteryStats = bss;
        mHandlerThread = new HandlerThread(TAG);
        mHandlerThread.start();
        mHandler = new PowerManagerHandler(mHandlerThread.getLooper());

        Watchdog.getInstance().addMonitor(this);
    }

    public void setPolicy(WindowManagerPolicy policy) {
        synchronized (mLock) {
            mPolicy = policy;
        }
    }

    public void systemReady(TwilightService twilight, DreamManagerService dreamManager) {
        synchronized (mLock) {
            mSystemReady = true;
            mDreamManager = dreamManager;

            PowerManager pm = (PowerManager)mContext.getSystemService(Context.POWER_SERVICE);
            mScreenBrightnessSettingMinimum = pm.getMinimumScreenBrightnessSetting();
            mScreenBrightnessSettingMaximum = pm.getMaximumScreenBrightnessSetting();
            mScreenBrightnessSettingDefault = pm.getDefaultScreenBrightnessSetting();

            mNotifier = new Notifier(mHandler.getLooper(), mContext, mBatteryStats,
                    createSuspendBlockerLocked("PowerManagerService.Broadcasts"),
                    mPolicy, mScreenOnListener);
            mDisplayPowerController = new DisplayPowerController(mHandler.getLooper(),
                    mContext, mNotifier, mLightsService, twilight,
                    createSuspendBlockerLocked("PowerManagerService.Display"),
                    mDisplayPowerControllerCallbacks, mHandler);

            mSettingsObserver = new SettingsObserver(mHandler);
            mAttentionLight = mLightsService.getLight(LightsService.LIGHT_ID_ATTENTION);

            // Register for broadcasts from other components of the system.
            IntentFilter filter = new IntentFilter();
            filter.addAction(Intent.ACTION_BATTERY_CHANGED);
            mContext.registerReceiver(new BatteryReceiver(), filter, null, mHandler);

            filter = new IntentFilter();
            filter.addAction(Intent.ACTION_BOOT_COMPLETED);
            mContext.registerReceiver(new BootCompletedReceiver(), filter, null, mHandler);

            filter = new IntentFilter();
            filter.addAction(Intent.ACTION_DREAMING_STARTED);
            filter.addAction(Intent.ACTION_DREAMING_STOPPED);
            mContext.registerReceiver(new DreamReceiver(), filter, null, mHandler);

            filter = new IntentFilter();
            filter.addAction(Intent.ACTION_USER_SWITCHED);
            mContext.registerReceiver(new UserSwitchedReceiver(), filter, null, mHandler);

            // Register for settings changes.
            final ContentResolver resolver = mContext.getContentResolver();
            resolver.registerContentObserver(Settings.Secure.getUriFor(
                    Settings.Secure.SCREENSAVER_ENABLED),
                    false, mSettingsObserver, UserHandle.USER_ALL);
            resolver.registerContentObserver(Settings.Secure.getUriFor(
                    Settings.Secure.SCREENSAVER_ACTIVATE_ON_SLEEP),
                    false, mSettingsObserver, UserHandle.USER_ALL);
            resolver.registerContentObserver(Settings.System.getUriFor(
                    Settings.System.SCREEN_OFF_TIMEOUT),
                    false, mSettingsObserver, UserHandle.USER_ALL);
            resolver.registerContentObserver(Settings.Global.getUriFor(
                    Settings.Global.STAY_ON_WHILE_PLUGGED_IN),
                    false, mSettingsObserver, UserHandle.USER_ALL);
            resolver.registerContentObserver(Settings.System.getUriFor(
                    Settings.System.SCREEN_BRIGHTNESS),
                    false, mSettingsObserver, UserHandle.USER_ALL);
            resolver.registerContentObserver(Settings.System.getUriFor(
                    Settings.System.SCREEN_BRIGHTNESS_MODE),
                    false, mSettingsObserver, UserHandle.USER_ALL);

            // Go.
            readConfigurationLocked();
            updateSettingsLocked();
            mDirty |= DIRTY_BATTERY_STATE;
            updatePowerStateLocked();
        }
    }

    private void readConfigurationLocked() {
        final Resources resources = mContext.getResources();

        mWakeUpWhenPluggedOrUnpluggedConfig = resources.getBoolean(
                com.android.internal.R.bool.config_unplugTurnsOnScreen);
        mDreamsSupportedConfig = resources.getBoolean(
                com.android.internal.R.bool.config_enableDreams);
    }

    private void updateSettingsLocked() {
        final ContentResolver resolver = mContext.getContentResolver();

        mDreamsEnabledSetting = (Settings.Secure.getIntForUser(resolver,
                Settings.Secure.SCREENSAVER_ENABLED, 0,
                UserHandle.USER_CURRENT) != 0);
        mDreamsActivateOnSleepSetting = (Settings.Secure.getIntForUser(resolver,
                Settings.Secure.SCREENSAVER_ACTIVATE_ON_SLEEP, 0,
                UserHandle.USER_CURRENT) != 0);
        mScreenOffTimeoutSetting = Settings.System.getIntForUser(resolver,
                Settings.System.SCREEN_OFF_TIMEOUT, DEFAULT_SCREEN_OFF_TIMEOUT,
                UserHandle.USER_CURRENT);
        mStayOnWhilePluggedInSetting = Settings.Global.getInt(resolver,
                Settings.Global.STAY_ON_WHILE_PLUGGED_IN, BatteryManager.BATTERY_PLUGGED_AC);

        final int oldScreenBrightnessSetting = mScreenBrightnessSetting;
        mScreenBrightnessSetting = Settings.System.getIntForUser(resolver,
                Settings.System.SCREEN_BRIGHTNESS, mScreenBrightnessSettingDefault,
                UserHandle.USER_CURRENT);
        if (oldScreenBrightnessSetting != mScreenBrightnessSetting) {
            mTemporaryScreenBrightnessSettingOverride = -1;
        }

        final float oldScreenAutoBrightnessAdjustmentSetting =
                mScreenAutoBrightnessAdjustmentSetting;
        mScreenAutoBrightnessAdjustmentSetting = Settings.System.getFloatForUser(resolver,
                Settings.System.SCREEN_AUTO_BRIGHTNESS_ADJ, 0.0f,
                UserHandle.USER_CURRENT);
        if (oldScreenAutoBrightnessAdjustmentSetting != mScreenAutoBrightnessAdjustmentSetting) {
            mTemporaryScreenAutoBrightnessAdjustmentSettingOverride = Float.NaN;
        }

        mScreenBrightnessModeSetting = Settings.System.getIntForUser(resolver,
                Settings.System.SCREEN_BRIGHTNESS_MODE,
                Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL, UserHandle.USER_CURRENT);

        mDirty |= DIRTY_SETTINGS;
    }

    private void handleSettingsChangedLocked() {
        updateSettingsLocked();
        updatePowerStateLocked();
    }

    @Override // Binder call
    public void acquireWakeLock(IBinder lock, int flags, String tag, WorkSource ws) {
        if (lock == null) {
            throw new IllegalArgumentException("lock must not be null");
        }
        PowerManager.validateWakeLockParameters(flags, tag);

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WAKE_LOCK, null);
        if (ws != null && ws.size() != 0) {
            mContext.enforceCallingOrSelfPermission(
                    android.Manifest.permission.UPDATE_DEVICE_STATS, null);
        } else {
            ws = null;
        }

        final int uid = Binder.getCallingUid();
        final int pid = Binder.getCallingPid();
        final long ident = Binder.clearCallingIdentity();
        try {
            acquireWakeLockInternal(lock, flags, tag, ws, uid, pid);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void acquireWakeLockInternal(IBinder lock, int flags, String tag, WorkSource ws,
            int uid, int pid) {
        synchronized (mLock) {
            if (DEBUG_SPEW) {
                Slog.d(TAG, "acquireWakeLockInternal: lock=" + Objects.hashCode(lock)
                        + ", flags=0x" + Integer.toHexString(flags)
                        + ", tag=\"" + tag + "\", ws=" + ws + ", uid=" + uid + ", pid=" + pid);
            }

            WakeLock wakeLock;
            int index = findWakeLockIndexLocked(lock);
            if (index >= 0) {
                wakeLock = mWakeLocks.get(index);
                if (!wakeLock.hasSameProperties(flags, tag, ws, uid, pid)) {
                    // Update existing wake lock.  This shouldn't happen but is harmless.
                    notifyWakeLockReleasedLocked(wakeLock);
                    wakeLock.updateProperties(flags, tag, ws, uid, pid);
                    notifyWakeLockAcquiredLocked(wakeLock);
                }
            } else {
                wakeLock = new WakeLock(lock, flags, tag, ws, uid, pid);
                try {
                    lock.linkToDeath(wakeLock, 0);
                } catch (RemoteException ex) {
                    throw new IllegalArgumentException("Wake lock is already dead.");
                }
                notifyWakeLockAcquiredLocked(wakeLock);
                mWakeLocks.add(wakeLock);
            }

            applyWakeLockFlagsOnAcquireLocked(wakeLock);
            mDirty |= DIRTY_WAKE_LOCKS;
            updatePowerStateLocked();
        }
    }

    private void applyWakeLockFlagsOnAcquireLocked(WakeLock wakeLock) {
        if ((wakeLock.mFlags & PowerManager.ACQUIRE_CAUSES_WAKEUP) != 0) {
            wakeUpNoUpdateLocked(SystemClock.uptimeMillis());
        }
    }

    @Override // Binder call
    public void releaseWakeLock(IBinder lock, int flags) {
        if (lock == null) {
            throw new IllegalArgumentException("lock must not be null");
        }

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WAKE_LOCK, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            releaseWakeLockInternal(lock, flags);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void releaseWakeLockInternal(IBinder lock, int flags) {
        synchronized (mLock) {
            if (DEBUG_SPEW) {
                Slog.d(TAG, "releaseWakeLockInternal: lock=" + Objects.hashCode(lock)
                        + ", flags=0x" + Integer.toHexString(flags));
            }

            int index = findWakeLockIndexLocked(lock);
            if (index < 0) {
                return;
            }

            WakeLock wakeLock = mWakeLocks.get(index);
            mWakeLocks.remove(index);
            notifyWakeLockReleasedLocked(wakeLock);
            wakeLock.mLock.unlinkToDeath(wakeLock, 0);

            if ((flags & PowerManager.WAIT_FOR_PROXIMITY_NEGATIVE) != 0) {
                mRequestWaitForNegativeProximity = true;
            }

            applyWakeLockFlagsOnReleaseLocked(wakeLock);
            mDirty |= DIRTY_WAKE_LOCKS;
            updatePowerStateLocked();
        }
    }

    private void handleWakeLockDeath(WakeLock wakeLock) {
        synchronized (mLock) {
            if (DEBUG_SPEW) {
                Slog.d(TAG, "handleWakeLockDeath: lock=" + Objects.hashCode(wakeLock.mLock));
            }

            int index = mWakeLocks.indexOf(wakeLock);
            if (index < 0) {
                return;
            }

            mWakeLocks.remove(index);
            notifyWakeLockReleasedLocked(wakeLock);

            applyWakeLockFlagsOnReleaseLocked(wakeLock);
            mDirty |= DIRTY_WAKE_LOCKS;
            updatePowerStateLocked();
        }
    }

    private void applyWakeLockFlagsOnReleaseLocked(WakeLock wakeLock) {
        if ((wakeLock.mFlags & PowerManager.ON_AFTER_RELEASE) != 0) {
            userActivityNoUpdateLocked(SystemClock.uptimeMillis(),
                    PowerManager.USER_ACTIVITY_EVENT_OTHER,
                    PowerManager.USER_ACTIVITY_FLAG_NO_CHANGE_LIGHTS,
                    wakeLock.mOwnerUid);
        }
    }

    @Override // Binder call
    public void updateWakeLockWorkSource(IBinder lock, WorkSource ws) {
        if (lock == null) {
            throw new IllegalArgumentException("lock must not be null");
        }

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WAKE_LOCK, null);
        if (ws != null && ws.size() != 0) {
            mContext.enforceCallingOrSelfPermission(
                    android.Manifest.permission.UPDATE_DEVICE_STATS, null);
        } else {
            ws = null;
        }

        final long ident = Binder.clearCallingIdentity();
        try {
            updateWakeLockWorkSourceInternal(lock, ws);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void updateWakeLockWorkSourceInternal(IBinder lock, WorkSource ws) {
        synchronized (mLock) {
            int index = findWakeLockIndexLocked(lock);
            if (index < 0) {
                throw new IllegalArgumentException("Wake lock not active");
            }

            WakeLock wakeLock = mWakeLocks.get(index);
            if (!wakeLock.hasSameWorkSource(ws)) {
                notifyWakeLockReleasedLocked(wakeLock);
                wakeLock.updateWorkSource(ws);
                notifyWakeLockAcquiredLocked(wakeLock);
            }
        }
    }

    private int findWakeLockIndexLocked(IBinder lock) {
        final int count = mWakeLocks.size();
        for (int i = 0; i < count; i++) {
            if (mWakeLocks.get(i).mLock == lock) {
                return i;
            }
        }
        return -1;
    }

    private void notifyWakeLockAcquiredLocked(WakeLock wakeLock) {
        if (mSystemReady) {
            mNotifier.onWakeLockAcquired(wakeLock.mFlags, wakeLock.mTag,
                    wakeLock.mOwnerUid, wakeLock.mOwnerPid, wakeLock.mWorkSource);
        }
    }

    private void notifyWakeLockReleasedLocked(WakeLock wakeLock) {
        if (mSystemReady) {
            mNotifier.onWakeLockReleased(wakeLock.mFlags, wakeLock.mTag,
                    wakeLock.mOwnerUid, wakeLock.mOwnerPid, wakeLock.mWorkSource);
        }
    }

    @Override // Binder call
    public boolean isWakeLockLevelSupported(int level) {
        final long ident = Binder.clearCallingIdentity();
        try {
            return isWakeLockLevelSupportedInternal(level);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private boolean isWakeLockLevelSupportedInternal(int level) {
        synchronized (mLock) {
            switch (level) {
                case PowerManager.PARTIAL_WAKE_LOCK:
                case PowerManager.SCREEN_DIM_WAKE_LOCK:
                case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
                case PowerManager.FULL_WAKE_LOCK:
                    return true;

                case PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK:
                    return mSystemReady && mDisplayPowerController.isProximitySensorAvailable();

                default:
                    return false;
            }
        }
    }

    @Override // Binder call
    public void userActivity(long eventTime, int event, int flags) {
        final long now = SystemClock.uptimeMillis();
        if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER)
                != PackageManager.PERMISSION_GRANTED) {
            // Once upon a time applications could call userActivity().
            // Now we require the DEVICE_POWER permission.  Log a warning and ignore the
            // request instead of throwing a SecurityException so we don't break old apps.
            synchronized (mLock) {
                if (now >= mLastWarningAboutUserActivityPermission + (5 * 60 * 1000)) {
                    mLastWarningAboutUserActivityPermission = now;
                    Slog.w(TAG, "Ignoring call to PowerManager.userActivity() because the "
                            + "caller does not have DEVICE_POWER permission.  "
                            + "Please fix your app!  "
                            + " pid=" + Binder.getCallingPid()
                            + " uid=" + Binder.getCallingUid());
                }
            }
            return;
        }

        if (eventTime > SystemClock.uptimeMillis()) {
            throw new IllegalArgumentException("event time must not be in the future");
        }

        final int uid = Binder.getCallingUid();
        final long ident = Binder.clearCallingIdentity();
        try {
            userActivityInternal(eventTime, event, flags, uid);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    // Called from native code.
    private void userActivityFromNative(long eventTime, int event, int flags) {
        userActivityInternal(eventTime, event, flags, Process.SYSTEM_UID);
    }

    private void userActivityInternal(long eventTime, int event, int flags, int uid) {
        synchronized (mLock) {
            if (userActivityNoUpdateLocked(eventTime, event, flags, uid)) {
                updatePowerStateLocked();
            }
        }
    }

    private boolean userActivityNoUpdateLocked(long eventTime, int event, int flags, int uid) {
        if (DEBUG_SPEW) {
            Slog.d(TAG, "userActivityNoUpdateLocked: eventTime=" + eventTime
                    + ", event=" + event + ", flags=0x" + Integer.toHexString(flags)
                    + ", uid=" + uid);
        }

        if (eventTime < mLastSleepTime || eventTime < mLastWakeTime
                || mWakefulness == WAKEFULNESS_ASLEEP || !mBootCompleted || !mSystemReady) {
            return false;
        }

        mNotifier.onUserActivity(event, uid);

        if ((flags & PowerManager.USER_ACTIVITY_FLAG_NO_CHANGE_LIGHTS) != 0) {
            if (eventTime > mLastUserActivityTimeNoChangeLights
                    && eventTime > mLastUserActivityTime) {
                mLastUserActivityTimeNoChangeLights = eventTime;
                mDirty |= DIRTY_USER_ACTIVITY;
                return true;
            }
        } else {
            if (eventTime > mLastUserActivityTime) {
                mLastUserActivityTime = eventTime;
                mDirty |= DIRTY_USER_ACTIVITY;
                return true;
            }
        }
        return false;
    }

    @Override // Binder call
    public void wakeUp(long eventTime) {
        if (eventTime > SystemClock.uptimeMillis()) {
            throw new IllegalArgumentException("event time must not be in the future");
        }

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            wakeUpInternal(eventTime);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    // Called from native code.
    private void wakeUpFromNative(long eventTime) {
        wakeUpInternal(eventTime);
    }

    private void wakeUpInternal(long eventTime) {
        synchronized (mLock) {
            if (wakeUpNoUpdateLocked(eventTime)) {
                updatePowerStateLocked();
            }
        }
    }

    private boolean wakeUpNoUpdateLocked(long eventTime) {
        if (DEBUG_SPEW) {
            Slog.d(TAG, "wakeUpNoUpdateLocked: eventTime=" + eventTime);
        }

        if (eventTime < mLastSleepTime || mWakefulness == WAKEFULNESS_AWAKE
                || !mBootCompleted || !mSystemReady) {
            return false;
        }

        switch (mWakefulness) {
            case WAKEFULNESS_ASLEEP:
                Slog.i(TAG, "Waking up from sleep...");
                mNotifier.onWakeUpStarted();
                mSendWakeUpFinishedNotificationWhenReady = true;
                mSendGoToSleepFinishedNotificationWhenReady = false;
                break;
            case WAKEFULNESS_DREAMING:
                Slog.i(TAG, "Waking up from dream...");
                break;
            case WAKEFULNESS_NAPPING:
                Slog.i(TAG, "Waking up from nap...");
                break;
        }

        mLastWakeTime = eventTime;
        mWakefulness = WAKEFULNESS_AWAKE;
        mDirty |= DIRTY_WAKEFULNESS;

        userActivityNoUpdateLocked(
                eventTime, PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID);
        return true;
    }

    @Override // Binder call
    public void goToSleep(long eventTime, int reason) {
        if (eventTime > SystemClock.uptimeMillis()) {
            throw new IllegalArgumentException("event time must not be in the future");
        }

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            goToSleepInternal(eventTime, reason);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    // Called from native code.
    private void goToSleepFromNative(long eventTime, int reason) {
        goToSleepInternal(eventTime, reason);
    }

    private void goToSleepInternal(long eventTime, int reason) {
        synchronized (mLock) {
            if (goToSleepNoUpdateLocked(eventTime, reason)) {
                updatePowerStateLocked();
            }
        }
    }

    private boolean goToSleepNoUpdateLocked(long eventTime, int reason) {
        if (DEBUG_SPEW) {
            Slog.d(TAG, "goToSleepNoUpdateLocked: eventTime=" + eventTime + ", reason=" + reason);
        }

        if (eventTime < mLastWakeTime || mWakefulness == WAKEFULNESS_ASLEEP
                || !mBootCompleted || !mSystemReady) {
            return false;
        }

        switch (reason) {
            case PowerManager.GO_TO_SLEEP_REASON_DEVICE_ADMIN:
                Slog.i(TAG, "Going to sleep due to device administration policy...");
                break;
            case PowerManager.GO_TO_SLEEP_REASON_TIMEOUT:
                Slog.i(TAG, "Going to sleep due to screen timeout...");
                break;
            default:
                Slog.i(TAG, "Going to sleep by user request...");
                reason = PowerManager.GO_TO_SLEEP_REASON_USER;
                break;
        }

        mLastSleepTime = eventTime;
        mDirty |= DIRTY_WAKEFULNESS;
        mWakefulness = WAKEFULNESS_ASLEEP;
        mNotifier.onGoToSleepStarted(reason);
        mSendGoToSleepFinishedNotificationWhenReady = true;
        mSendWakeUpFinishedNotificationWhenReady = false;

        // Report the number of wake locks that will be cleared by going to sleep.
        int numWakeLocksCleared = 0;
        final int numWakeLocks = mWakeLocks.size();
        for (int i = 0; i < numWakeLocks; i++) {
            final WakeLock wakeLock = mWakeLocks.get(i);
            switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
                case PowerManager.FULL_WAKE_LOCK:
                case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
                case PowerManager.SCREEN_DIM_WAKE_LOCK:
                    numWakeLocksCleared += 1;
                    break;
            }
        }
        EventLog.writeEvent(EventLogTags.POWER_SLEEP_REQUESTED, numWakeLocksCleared);
        return true;
    }

    @Override // Binder call
    public void nap(long eventTime) {
        if (eventTime > SystemClock.uptimeMillis()) {
            throw new IllegalArgumentException("event time must not be in the future");
        }

        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            napInternal(eventTime);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void napInternal(long eventTime) {
        synchronized (mLock) {
            if (napNoUpdateLocked(eventTime)) {
                updatePowerStateLocked();
            }
        }
    }

    private boolean napNoUpdateLocked(long eventTime) {
        if (DEBUG_SPEW) {
            Slog.d(TAG, "napNoUpdateLocked: eventTime=" + eventTime);
        }

        if (eventTime < mLastWakeTime || mWakefulness != WAKEFULNESS_AWAKE
                || !mBootCompleted || !mSystemReady) {
            return false;
        }

        Slog.i(TAG, "Nap time...");

        mDirty |= DIRTY_WAKEFULNESS;
        mWakefulness = WAKEFULNESS_NAPPING;
        return true;
    }

    /**
     * Updates the global power state based on dirty bits recorded in mDirty.
     *
     * This is the main function that performs power state transitions.
     * We centralize them here so that we can recompute the power state completely
     * each time something important changes, and ensure that we do it the same
     * way each time.  The point is to gather all of the transition logic here.
     */
    private void updatePowerStateLocked() {
        if (!mSystemReady || mDirty == 0) {
            return;
        }

        // Phase 0: Basic state updates.
        updateIsPoweredLocked(mDirty);
        updateStayOnLocked(mDirty);

        // Phase 1: Update wakefulness.
        // Loop because the wake lock and user activity computations are influenced
        // by changes in wakefulness.
        final long now = SystemClock.uptimeMillis();
        int dirtyPhase2 = 0;
        for (;;) {
            int dirtyPhase1 = mDirty;
            dirtyPhase2 |= dirtyPhase1;
            mDirty = 0;

            updateWakeLockSummaryLocked(dirtyPhase1);
            updateUserActivitySummaryLocked(now, dirtyPhase1);
            if (!updateWakefulnessLocked(dirtyPhase1)) {
                break;
            }
        }

        // Phase 2: Update dreams and display power state.
        updateDreamLocked(dirtyPhase2);
        updateDisplayPowerStateLocked(dirtyPhase2);

        // Phase 3: Send notifications, if needed.
        sendPendingNotificationsLocked();

        // Phase 4: Update suspend blocker.
        // Because we might release the last suspend blocker here, we need to make sure
        // we finished everything else first!
        updateSuspendBlockerLocked();
    }

    private void sendPendingNotificationsLocked() {
        if (mDisplayReady) {
            if (mSendWakeUpFinishedNotificationWhenReady) {
                mSendWakeUpFinishedNotificationWhenReady = false;
                mNotifier.onWakeUpFinished();
            }
            if (mSendGoToSleepFinishedNotificationWhenReady) {
                mSendGoToSleepFinishedNotificationWhenReady = false;
                mNotifier.onGoToSleepFinished();
            }
        }
    }

    /**
     * Updates the value of mIsPowered.
     * Sets DIRTY_IS_POWERED if a change occurred.
     */
    private void updateIsPoweredLocked(int dirty) {
        if ((dirty & DIRTY_BATTERY_STATE) != 0) {
            final boolean wasPowered = mIsPowered;
            final int oldPlugType = mPlugType;
            mIsPowered = mBatteryService.isPowered(BatteryManager.BATTERY_PLUGGED_ANY);
            mPlugType = mBatteryService.getPlugType();

            if (DEBUG) {
                Slog.d(TAG, "updateIsPoweredLocked: wasPowered=" + wasPowered
                        + ", mIsPowered=" + mIsPowered
                        + ", oldPlugType=" + oldPlugType
                        + ", mPlugType=" + mPlugType);
            }

            if (wasPowered != mIsPowered || oldPlugType != mPlugType) {
                mDirty |= DIRTY_IS_POWERED;

                // Treat plugging and unplugging the devices as a user activity.
                // Users find it disconcerting when they plug or unplug the device
                // and it shuts off right away.
                // Some devices also wake the device when plugged or unplugged because
                // they don't have a charging LED.
                final long now = SystemClock.uptimeMillis();
                if (shouldWakeUpWhenPluggedOrUnpluggedLocked(wasPowered, oldPlugType)) {
                    wakeUpNoUpdateLocked(now);
                }
                userActivityNoUpdateLocked(
                        now, PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID);
            }
        }
    }

    private boolean shouldWakeUpWhenPluggedOrUnpluggedLocked(boolean wasPowered, int oldPlugType) {
        if (mWakeUpWhenPluggedOrUnpluggedConfig) {
            // FIXME: Need more accurate detection of wireless chargers.
            //
            // We are unable to accurately detect whether the device is resting on the
            // charger unless it is actually receiving power.  This causes us some grief
            // because the device might not appear to be plugged into the wireless charger
            // unless it actually charging.
            //
            // To avoid spuriously waking the screen, we apply a special policy to
            // wireless chargers.
            //
            // 1. Don't wake the device when unplugged from wireless charger because
            //    it might be that the device is still resting on the wireless charger
            //    but is not receiving power anymore because the battery is full.
            //
            // 2. Don't wake the device when plugged into a wireless charger if the
            //    battery already appears to be mostly full.  This situation may indicate
            //    that the device was resting on the charger the whole time and simply
            //    wasn't receiving power because the battery was full.  We can't tell
            //    whether the device was just placed on the charger or whether it has
            //    been there for half of the night slowly discharging until it hit
            //    the point where it needed to start charging again.
            if (wasPowered && !mIsPowered
                    && oldPlugType == BatteryManager.BATTERY_PLUGGED_WIRELESS) {
                return false;
            }
            if (!wasPowered && mIsPowered
                    && mPlugType == BatteryManager.BATTERY_PLUGGED_WIRELESS
                    && mBatteryService.getBatteryLevel() >=
                            WIRELESS_CHARGER_TURN_ON_BATTERY_LEVEL_LIMIT) {
                return false;
            }
            return true;
        }
        return false;
    }

    /**
     * Updates the value of mStayOn.
     * Sets DIRTY_STAY_ON if a change occurred.
     */
    private void updateStayOnLocked(int dirty) {
        if ((dirty & (DIRTY_BATTERY_STATE | DIRTY_SETTINGS)) != 0) {
            if (mStayOnWhilePluggedInSetting != 0
                    && !isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked()) {
                mStayOn = mBatteryService.isPowered(mStayOnWhilePluggedInSetting);
            } else {
                mStayOn = false;
            }
        }
    }

    /**
     * Updates the value of mWakeLockSummary to summarize the state of all active wake locks.
     * Note that most wake-locks are ignored when the system is asleep.
     *
     * This function must have no other side-effects.
     */
    private void updateWakeLockSummaryLocked(int dirty) {
        if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_WAKEFULNESS)) != 0) {
            mWakeLockSummary = 0;

            final int numWakeLocks = mWakeLocks.size();
            for (int i = 0; i < numWakeLocks; i++) {
                final WakeLock wakeLock = mWakeLocks.get(i);
                switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
                    case PowerManager.PARTIAL_WAKE_LOCK:
                        mWakeLockSummary |= WAKE_LOCK_CPU;
                        break;
                    case PowerManager.FULL_WAKE_LOCK:
                        if (mWakefulness != WAKEFULNESS_ASLEEP) {
                            mWakeLockSummary |= WAKE_LOCK_CPU
                                    | WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_BUTTON_BRIGHT;
                        }
                        break;
                    case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
                        if (mWakefulness != WAKEFULNESS_ASLEEP) {
                            mWakeLockSummary |= WAKE_LOCK_CPU | WAKE_LOCK_SCREEN_BRIGHT;
                        }
                        break;
                    case PowerManager.SCREEN_DIM_WAKE_LOCK:
                        if (mWakefulness != WAKEFULNESS_ASLEEP) {
                            mWakeLockSummary |= WAKE_LOCK_CPU | WAKE_LOCK_SCREEN_DIM;
                        }
                        break;
                    case PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK:
                        if (mWakefulness != WAKEFULNESS_ASLEEP) {
                            mWakeLockSummary |= WAKE_LOCK_CPU | WAKE_LOCK_PROXIMITY_SCREEN_OFF;
                        }
                        break;
                }
            }

            if (DEBUG_SPEW) {
                Slog.d(TAG, "updateWakeLockSummaryLocked: mWakefulness="
                        + wakefulnessToString(mWakefulness)
                        + ", mWakeLockSummary=0x" + Integer.toHexString(mWakeLockSummary));
            }
        }
    }

    /**
     * Updates the value of mUserActivitySummary to summarize the user requested
     * state of the system such as whether the screen should be bright or dim.
     * Note that user activity is ignored when the system is asleep.
     *
     * This function must have no other side-effects.
     */
    private void updateUserActivitySummaryLocked(long now, int dirty) {
        // Update the status of the user activity timeout timer.
        if ((dirty & (DIRTY_USER_ACTIVITY | DIRTY_WAKEFULNESS | DIRTY_SETTINGS)) != 0) {
            mHandler.removeMessages(MSG_USER_ACTIVITY_TIMEOUT);

            long nextTimeout = 0;
            if (mWakefulness != WAKEFULNESS_ASLEEP) {
                final int screenOffTimeout = getScreenOffTimeoutLocked();
                final int screenDimDuration = getScreenDimDurationLocked(screenOffTimeout);

                mUserActivitySummary = 0;
                if (mLastUserActivityTime >= mLastWakeTime) {
                    nextTimeout = mLastUserActivityTime
                            + screenOffTimeout - screenDimDuration;
                    if (now < nextTimeout) {
                        mUserActivitySummary |= USER_ACTIVITY_SCREEN_BRIGHT;
                    } else {
                        nextTimeout = mLastUserActivityTime + screenOffTimeout;
                        if (now < nextTimeout) {
                            mUserActivitySummary |= USER_ACTIVITY_SCREEN_DIM;
                        }
                    }
                }
                if (mUserActivitySummary == 0
                        && mLastUserActivityTimeNoChangeLights >= mLastWakeTime) {
                    nextTimeout = mLastUserActivityTimeNoChangeLights + screenOffTimeout;
                    if (now < nextTimeout
                            && mDisplayPowerRequest.screenState
                                    != DisplayPowerRequest.SCREEN_STATE_OFF) {
                        mUserActivitySummary = mDisplayPowerRequest.screenState
                                == DisplayPowerRequest.SCREEN_STATE_BRIGHT ?
                                USER_ACTIVITY_SCREEN_BRIGHT : USER_ACTIVITY_SCREEN_DIM;
                    }
                }
                if (mUserActivitySummary != 0) {
                    Message msg = mHandler.obtainMessage(MSG_USER_ACTIVITY_TIMEOUT);
                    msg.setAsynchronous(true);
                    mHandler.sendMessageAtTime(msg, nextTimeout);
                }
            } else {
                mUserActivitySummary = 0;
            }

            if (DEBUG_SPEW) {
                Slog.d(TAG, "updateUserActivitySummaryLocked: mWakefulness="
                        + wakefulnessToString(mWakefulness)
                        + ", mUserActivitySummary=0x" + Integer.toHexString(mUserActivitySummary)
                        + ", nextTimeout=" + TimeUtils.formatUptime(nextTimeout));
            }
        }
    }

    /**
     * Called when a user activity timeout has occurred.
     * Simply indicates that something about user activity has changed so that the new
     * state can be recomputed when the power state is updated.
     *
     * This function must have no other side-effects besides setting the dirty
     * bit and calling update power state.  Wakefulness transitions are handled elsewhere.
     */
    private void handleUserActivityTimeout() { // runs on handler thread
        synchronized (mLock) {
            if (DEBUG_SPEW) {
                Slog.d(TAG, "handleUserActivityTimeout");
            }

            mDirty |= DIRTY_USER_ACTIVITY;
            updatePowerStateLocked();
        }
    }

    private int getScreenOffTimeoutLocked() {
        int timeout = mScreenOffTimeoutSetting;
        if (isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked()) {
            timeout = Math.min(timeout, mMaximumScreenOffTimeoutFromDeviceAdmin);
        }
        if (mUserActivityTimeoutOverrideFromWindowManager >= 0) {
            timeout = (int)Math.min(timeout, mUserActivityTimeoutOverrideFromWindowManager);
        }
        return Math.max(timeout, MINIMUM_SCREEN_OFF_TIMEOUT);
    }

    private int getScreenDimDurationLocked(int screenOffTimeout) {
        return Math.min(SCREEN_DIM_DURATION,
                (int)(screenOffTimeout * MAXIMUM_SCREEN_DIM_RATIO));
    }

    /**
     * Updates the wakefulness of the device.
     *
     * This is the function that decides whether the device should start napping
     * based on the current wake locks and user activity state.  It may modify mDirty
     * if the wakefulness changes.
     *
     * Returns true if the wakefulness changed and we need to restart power state calculation.
     */
    private boolean updateWakefulnessLocked(int dirty) {
        boolean changed = false;
        if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_USER_ACTIVITY | DIRTY_BOOT_COMPLETED
                | DIRTY_WAKEFULNESS | DIRTY_STAY_ON)) != 0) {
            if (mWakefulness == WAKEFULNESS_AWAKE && isItBedTimeYetLocked()) {
                if (DEBUG_SPEW) {
                    Slog.d(TAG, "updateWakefulnessLocked: Bed time...");
                }
                final long time = SystemClock.uptimeMillis();
                if (mDreamsActivateOnSleepSetting) {
                    changed = napNoUpdateLocked(time);
                } else {
                    changed = goToSleepNoUpdateLocked(time,
                            PowerManager.GO_TO_SLEEP_REASON_TIMEOUT);
                }
            }
        }
        return changed;
    }

    /**
     * Returns true if the device should go to sleep now.
     * Also used when exiting a dream to determine whether we should go back
     * to being fully awake or else go to sleep for good.
     */
    private boolean isItBedTimeYetLocked() {
        return mBootCompleted && !isScreenBeingKeptOnLocked();
    }

    /**
     * Returns true if the screen is being kept on by a wake lock, user activity
     * or the stay on while powered setting.
     */
    private boolean isScreenBeingKeptOnLocked() {
        return mStayOn
                || (mWakeLockSummary & (WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_SCREEN_DIM
                        | WAKE_LOCK_PROXIMITY_SCREEN_OFF)) != 0
                || (mUserActivitySummary & (USER_ACTIVITY_SCREEN_BRIGHT
                        | USER_ACTIVITY_SCREEN_DIM)) != 0;
    }

    /**
     * Determines whether to post a message to the sandman to update the dream state.
     */
    private void updateDreamLocked(int dirty) {
        if ((dirty & (DIRTY_WAKEFULNESS
                | DIRTY_USER_ACTIVITY
                | DIRTY_WAKE_LOCKS
                | DIRTY_BOOT_COMPLETED
                | DIRTY_SETTINGS
                | DIRTY_IS_POWERED
                | DIRTY_STAY_ON
                | DIRTY_BATTERY_STATE)) != 0) {
            scheduleSandmanLocked();
        }
    }

    private void scheduleSandmanLocked() {
        if (!mSandmanScheduled) {
            mSandmanScheduled = true;
            Message msg = mHandler.obtainMessage(MSG_SANDMAN);
            msg.setAsynchronous(true);
            mHandler.sendMessage(msg);
        }
    }

    /**
     * Called when the device enters or exits a napping or dreaming state.
     *
     * We do this asynchronously because we must call out of the power manager to start
     * the dream and we don't want to hold our lock while doing so.  There is a risk that
     * the device will wake or go to sleep in the meantime so we have to handle that case.
     */
    private void handleSandman() { // runs on handler thread
        // Handle preconditions.
        boolean startDreaming = false;
        synchronized (mLock) {
            mSandmanScheduled = false;
            boolean canDream = canDreamLocked();
            if (DEBUG_SPEW) {
                Log.d(TAG, "handleSandman: canDream=" + canDream
                        + ", mWakefulness=" + wakefulnessToString(mWakefulness));
            }

            if (canDream && mWakefulness == WAKEFULNESS_NAPPING) {
                startDreaming = true;
            }
        }

        // Start dreaming if needed.
        // We only control the dream on the handler thread, so we don't need to worry about
        // concurrent attempts to start or stop the dream.
        boolean isDreaming = false;
        if (mDreamManager != null) {
            if (startDreaming) {
                mDreamManager.startDream();
            }
            isDreaming = mDreamManager.isDreaming();
        }

        // Update dream state.
        // We might need to stop the dream again if the preconditions changed.
        boolean continueDreaming = false;
        synchronized (mLock) {
            if (isDreaming && canDreamLocked()) {
                if (mWakefulness == WAKEFULNESS_NAPPING) {
                    mWakefulness = WAKEFULNESS_DREAMING;
                    mDirty |= DIRTY_WAKEFULNESS;
                    updatePowerStateLocked();
                    continueDreaming = true;
                } else if (mWakefulness == WAKEFULNESS_DREAMING) {
                    continueDreaming = true;
                }
            }
            if (!continueDreaming) {
                handleDreamFinishedLocked();
            }
        }

        // Stop dreaming if needed.
        // It's possible that something else changed to make us need to start the dream again.
        // If so, then the power manager will have posted another message to the handler
        // to take care of it later.
        if (mDreamManager != null) {
            if (!continueDreaming) {
                mDreamManager.stopDream();
            }
        }
    }

    /**
     * Returns true if the device is allowed to dream in its current state
     * assuming that it is currently napping or dreaming.
     */
    private boolean canDreamLocked() {
        return mDreamsSupportedConfig
                && mDreamsEnabledSetting
                && mDisplayPowerRequest.screenState != DisplayPowerRequest.SCREEN_STATE_OFF
                && mBootCompleted
                && (mIsPowered || isScreenBeingKeptOnLocked());
    }

    /**
     * Called when a dream is ending to figure out what to do next.
     */
    private void handleDreamFinishedLocked() {
        if (mWakefulness == WAKEFULNESS_NAPPING
                || mWakefulness == WAKEFULNESS_DREAMING) {
            if (isItBedTimeYetLocked()) {
                goToSleepNoUpdateLocked(SystemClock.uptimeMillis(),
                        PowerManager.GO_TO_SLEEP_REASON_TIMEOUT);
                updatePowerStateLocked();
            } else {
                wakeUpNoUpdateLocked(SystemClock.uptimeMillis());
                updatePowerStateLocked();
            }
        }
    }

    /**
     * Updates the display power state asynchronously.
     * When the update is finished, mDisplayReady will be set to true.  The display
     * controller posts a message to tell us when the actual display power state
     * has been updated so we come back here to double-check and finish up.
     *
     * This function recalculates the display power state each time.
     */
    private void updateDisplayPowerStateLocked(int dirty) {
        if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_USER_ACTIVITY | DIRTY_WAKEFULNESS
                | DIRTY_ACTUAL_DISPLAY_POWER_STATE_UPDATED | DIRTY_BOOT_COMPLETED
                | DIRTY_SETTINGS)) != 0) {
            int newScreenState = getDesiredScreenPowerState();
            if (newScreenState != mDisplayPowerRequest.screenState) {
                if (newScreenState == DisplayPowerRequest.SCREEN_STATE_OFF
                        && mDisplayPowerRequest.screenState
                                != DisplayPowerRequest.SCREEN_STATE_OFF) {
                    mLastScreenOffEventElapsedRealTime = SystemClock.elapsedRealtime();
                }

                mDisplayPowerRequest.screenState = newScreenState;
                nativeSetPowerState(
                        newScreenState != DisplayPowerRequest.SCREEN_STATE_OFF,
                        newScreenState == DisplayPowerRequest.SCREEN_STATE_BRIGHT);
            }

            int screenBrightness = mScreenBrightnessSettingDefault;
            float screenAutoBrightnessAdjustment = 0.0f;
            boolean autoBrightness = (mScreenBrightnessModeSetting ==
                    Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);
            if (isValidBrightness(mScreenBrightnessOverrideFromWindowManager)) {
                screenBrightness = mScreenBrightnessOverrideFromWindowManager;
                autoBrightness = false;
            } else if (isValidBrightness(mTemporaryScreenBrightnessSettingOverride)) {
                screenBrightness = mTemporaryScreenBrightnessSettingOverride;
            } else if (isValidBrightness(mScreenBrightnessSetting)) {
                screenBrightness = mScreenBrightnessSetting;
            }
            if (autoBrightness) {
                screenBrightness = mScreenBrightnessSettingDefault;
                if (isValidAutoBrightnessAdjustment(
                        mTemporaryScreenAutoBrightnessAdjustmentSettingOverride)) {
                    screenAutoBrightnessAdjustment =
                            mTemporaryScreenAutoBrightnessAdjustmentSettingOverride;
                } else if (isValidAutoBrightnessAdjustment(
                        mScreenAutoBrightnessAdjustmentSetting)) {
                    screenAutoBrightnessAdjustment = mScreenAutoBrightnessAdjustmentSetting;
                }
            }
            screenBrightness = Math.max(Math.min(screenBrightness,
                    mScreenBrightnessSettingMaximum), mScreenBrightnessSettingMinimum);
            screenAutoBrightnessAdjustment = Math.max(Math.min(
                    screenAutoBrightnessAdjustment, 1.0f), -1.0f);
            mDisplayPowerRequest.screenBrightness = screenBrightness;
            mDisplayPowerRequest.screenAutoBrightnessAdjustment =
                    screenAutoBrightnessAdjustment;
            mDisplayPowerRequest.useAutoBrightness = autoBrightness;

            mDisplayPowerRequest.useProximitySensor = shouldUseProximitySensorLocked();

            mDisplayReady = mDisplayPowerController.requestPowerState(mDisplayPowerRequest,
                    mRequestWaitForNegativeProximity);
            mRequestWaitForNegativeProximity = false;

            if (DEBUG_SPEW) {
                Slog.d(TAG, "updateScreenStateLocked: displayReady=" + mDisplayReady
                        + ", newScreenState=" + newScreenState
                        + ", mWakefulness=" + mWakefulness
                        + ", mWakeLockSummary=0x" + Integer.toHexString(mWakeLockSummary)
                        + ", mUserActivitySummary=0x" + Integer.toHexString(mUserActivitySummary)
                        + ", mBootCompleted=" + mBootCompleted);
            }
        }
    }

    private static boolean isValidBrightness(int value) {
        return value >= 0 && value <= 255;
    }

    private static boolean isValidAutoBrightnessAdjustment(float value) {
        // Handles NaN by always returning false.
        return value >= -1.0f && value <= 1.0f;
    }

    private int getDesiredScreenPowerState() {
        if (mWakefulness == WAKEFULNESS_ASLEEP) {
            return DisplayPowerRequest.SCREEN_STATE_OFF;
        }

        if ((mWakeLockSummary & WAKE_LOCK_SCREEN_BRIGHT) != 0
                || (mUserActivitySummary & USER_ACTIVITY_SCREEN_BRIGHT) != 0
                || !mBootCompleted) {
            return DisplayPowerRequest.SCREEN_STATE_BRIGHT;
        }

        return DisplayPowerRequest.SCREEN_STATE_DIM;
    }

    private final DisplayPowerController.Callbacks mDisplayPowerControllerCallbacks =
            new DisplayPowerController.Callbacks() {
        @Override
        public void onStateChanged() {
            mDirty |= DIRTY_ACTUAL_DISPLAY_POWER_STATE_UPDATED;
            updatePowerStateLocked();
        }

        @Override
        public void onProximityNegative() {
            userActivityNoUpdateLocked(SystemClock.uptimeMillis(),
                    PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID);
            updatePowerStateLocked();
        }
    };

    private boolean shouldUseProximitySensorLocked() {
        return (mWakeLockSummary & WAKE_LOCK_PROXIMITY_SCREEN_OFF) != 0;
    }

    /**
     * Updates the suspend blocker that keeps the CPU alive.
     *
     * This function must have no other side-effects.
     */
    private void updateSuspendBlockerLocked() {
        boolean wantCpu = isCpuNeededLocked();
        if (wantCpu != mHoldingWakeLockSuspendBlocker) {
            mHoldingWakeLockSuspendBlocker = wantCpu;
            if (wantCpu) {
                if (DEBUG) {
                    Slog.d(TAG, "updateSuspendBlockerLocked: Acquiring suspend blocker.");
                }
                mWakeLockSuspendBlocker.acquire();
            } else {
                if (DEBUG) {
                    Slog.d(TAG, "updateSuspendBlockerLocked: Releasing suspend blocker.");
                }
                mWakeLockSuspendBlocker.release();
            }
        }
    }

    private boolean isCpuNeededLocked() {
        return !mBootCompleted
                || mWakeLockSummary != 0
                || mUserActivitySummary != 0
                || mDisplayPowerRequest.screenState != DisplayPowerRequest.SCREEN_STATE_OFF
                || !mDisplayReady;
    }

    @Override // Binder call
    public boolean isScreenOn() {
        final long ident = Binder.clearCallingIdentity();
        try {
            return isScreenOnInternal();
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private boolean isScreenOnInternal() {
        synchronized (mLock) {
            return !mSystemReady
                    || mDisplayPowerRequest.screenState != DisplayPowerRequest.SCREEN_STATE_OFF;
        }
    }

    private void handleBatteryStateChangedLocked() {
        mDirty |= DIRTY_BATTERY_STATE;
        updatePowerStateLocked();
    }

    private void handleBootCompletedLocked() {
        final long now = SystemClock.uptimeMillis();
        mBootCompleted = true;
        mDirty |= DIRTY_BOOT_COMPLETED;
        userActivityNoUpdateLocked(
                now, PowerManager.USER_ACTIVITY_EVENT_OTHER, 0, Process.SYSTEM_UID);
        updatePowerStateLocked();
    }

    /**
     * Reboot the device, passing 'reason' (may be null)
     * to the underlying __reboot system call.  Should not return.
     */
    @Override // Binder call
    public void reboot(boolean confirm, String reason, boolean wait) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.REBOOT, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            rebootInternal(false, confirm, reason, wait);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    /**
     * Shutdown the devic, passing 'reason' (may be null)
     * to the underlying __reboot system call.  Should not return.
     */
    @Override // Binder call
    public void shutdown(boolean confirm, boolean wait) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.REBOOT, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            rebootInternal(true, confirm, null, wait);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void rebootInternal(final boolean shutdown, final boolean confirm,
            final String reason, boolean wait) {
        if (mHandler == null || !mSystemReady) {
            throw new IllegalStateException("Too early to call reboot()");
        }

        Runnable runnable = new Runnable() {
            public void run() {
                synchronized (this) {
                    if (shutdown) {
                        ShutdownThread.shutdown(mContext, confirm);
                    } else {
                        ShutdownThread.reboot(mContext, reason, confirm);
                    }
                }
            }
        };

        // ShutdownThread must run on a looper capable of displaying the UI.
        Message msg = Message.obtain(mHandler, runnable);
        msg.setAsynchronous(true);
        mHandler.sendMessage(msg);

        // PowerManager.reboot() is documented not to return so just wait for the inevitable.
        if (wait) {
            synchronized (runnable) {
                while (true) {
                    try {
                        runnable.wait();
                    } catch (InterruptedException e) {
                    }
                }
            }
        }
    }

    /**
     * Crash the runtime (causing a complete restart of the Android framework).
     * Requires REBOOT permission.  Mostly for testing.  Should not return.
     */
    @Override // Binder call
    public void crash(String message) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.REBOOT, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            crashInternal(message);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void crashInternal(final String message) {
        Thread t = new Thread("PowerManagerService.crash()") {
            public void run() {
                throw new RuntimeException(message);
            }
        };
        try {
            t.start();
            t.join();
        } catch (InterruptedException e) {
            Log.wtf(TAG, e);
        }
    }

    /**
     * Set the setting that determines whether the device stays on when plugged in.
     * The argument is a bit string, with each bit specifying a power source that,
     * when the device is connected to that source, causes the device to stay on.
     * See {@link android.os.BatteryManager} for the list of power sources that
     * can be specified. Current values include {@link android.os.BatteryManager#BATTERY_PLUGGED_AC}
     * and {@link android.os.BatteryManager#BATTERY_PLUGGED_USB}
     *
     * Used by "adb shell svc power stayon ..."
     *
     * @param val an {@code int} containing the bits that specify which power sources
     * should cause the device to stay on.
     */
    @Override // Binder call
    public void setStayOnSetting(int val) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WRITE_SETTINGS, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            setStayOnSettingInternal(val);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setStayOnSettingInternal(int val) {
        Settings.Global.putInt(mContext.getContentResolver(),
                Settings.Global.STAY_ON_WHILE_PLUGGED_IN, val);
    }

    /**
     * Used by device administration to set the maximum screen off timeout.
     *
     * This method must only be called by the device administration policy manager.
     */
    @Override // Binder call
    public void setMaximumScreenOffTimeoutFromDeviceAdmin(int timeMs) {
        final long ident = Binder.clearCallingIdentity();
        try {
            setMaximumScreenOffTimeoutFromDeviceAdminInternal(timeMs);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setMaximumScreenOffTimeoutFromDeviceAdminInternal(int timeMs) {
        synchronized (mLock) {
            mMaximumScreenOffTimeoutFromDeviceAdmin = timeMs;
            mDirty |= DIRTY_SETTINGS;
            updatePowerStateLocked();
        }
    }

    private boolean isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked() {
        return mMaximumScreenOffTimeoutFromDeviceAdmin >= 0
                && mMaximumScreenOffTimeoutFromDeviceAdmin < Integer.MAX_VALUE;
    }

    /**
     * Used by the phone application to make the attention LED flash when ringing.
     */
    @Override // Binder call
    public void setAttentionLight(boolean on, int color) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            setAttentionLightInternal(on, color);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setAttentionLightInternal(boolean on, int color) {
        LightsService.Light light;
        synchronized (mLock) {
            if (!mSystemReady) {
                return;
            }
            light = mAttentionLight;
        }

        // Control light outside of lock.
        light.setFlashing(color, LightsService.LIGHT_FLASH_HARDWARE, (on ? 3 : 0), 0);
    }

    /**
     * Used by the Watchdog.
     */
    public long timeSinceScreenWasLastOn() {
        synchronized (mLock) {
            if (mDisplayPowerRequest.screenState != DisplayPowerRequest.SCREEN_STATE_OFF) {
                return 0;
            }
            return SystemClock.elapsedRealtime() - mLastScreenOffEventElapsedRealTime;
        }
    }

    /**
     * Used by the window manager to override the screen brightness based on the
     * current foreground activity.
     *
     * This method must only be called by the window manager.
     *
     * @param brightness The overridden brightness, or -1 to disable the override.
     */
    public void setScreenBrightnessOverrideFromWindowManager(int brightness) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            setScreenBrightnessOverrideFromWindowManagerInternal(brightness);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setScreenBrightnessOverrideFromWindowManagerInternal(int brightness) {
        synchronized (mLock) {
            if (mScreenBrightnessOverrideFromWindowManager != brightness) {
                mScreenBrightnessOverrideFromWindowManager = brightness;
                mDirty |= DIRTY_SETTINGS;
                updatePowerStateLocked();
            }
        }
    }

    /**
     * Used by the window manager to override the button brightness based on the
     * current foreground activity.
     *
     * This method must only be called by the window manager.
     *
     * @param brightness The overridden brightness, or -1 to disable the override.
     */
    public void setButtonBrightnessOverrideFromWindowManager(int brightness) {
        // Do nothing.
        // Button lights are not currently supported in the new implementation.
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);
    }

    /**
     * Used by the window manager to override the user activity timeout based on the
     * current foreground activity.  It can only be used to make the timeout shorter
     * than usual, not longer.
     *
     * This method must only be called by the window manager.
     *
     * @param timeoutMillis The overridden timeout, or -1 to disable the override.
     */
    public void setUserActivityTimeoutOverrideFromWindowManager(long timeoutMillis) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            setUserActivityTimeoutOverrideFromWindowManagerInternal(timeoutMillis);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setUserActivityTimeoutOverrideFromWindowManagerInternal(long timeoutMillis) {
        synchronized (mLock) {
            if (mUserActivityTimeoutOverrideFromWindowManager != timeoutMillis) {
                mUserActivityTimeoutOverrideFromWindowManager = timeoutMillis;
                mDirty |= DIRTY_SETTINGS;
                updatePowerStateLocked();
            }
        }
    }

    /**
     * Used by the settings application and brightness control widgets to
     * temporarily override the current screen brightness setting so that the
     * user can observe the effect of an intended settings change without applying
     * it immediately.
     *
     * The override will be canceled when the setting value is next updated.
     *
     * @param brightness The overridden brightness.
     *
     * @see Settings.System#SCREEN_BRIGHTNESS
     */
    @Override // Binder call
    public void setTemporaryScreenBrightnessSettingOverride(int brightness) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            setTemporaryScreenBrightnessSettingOverrideInternal(brightness);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setTemporaryScreenBrightnessSettingOverrideInternal(int brightness) {
        synchronized (mLock) {
            if (mTemporaryScreenBrightnessSettingOverride != brightness) {
                mTemporaryScreenBrightnessSettingOverride = brightness;
                mDirty |= DIRTY_SETTINGS;
                updatePowerStateLocked();
            }
        }
    }

    /**
     * Used by the settings application and brightness control widgets to
     * temporarily override the current screen auto-brightness adjustment setting so that the
     * user can observe the effect of an intended settings change without applying
     * it immediately.
     *
     * The override will be canceled when the setting value is next updated.
     *
     * @param adj The overridden brightness, or Float.NaN to disable the override.
     *
     * @see Settings.System#SCREEN_AUTO_BRIGHTNESS_ADJ
     */
    @Override // Binder call
    public void setTemporaryScreenAutoBrightnessAdjustmentSettingOverride(float adj) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);

        final long ident = Binder.clearCallingIdentity();
        try {
            setTemporaryScreenAutoBrightnessAdjustmentSettingOverrideInternal(adj);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
    }

    private void setTemporaryScreenAutoBrightnessAdjustmentSettingOverrideInternal(float adj) {
        synchronized (mLock) {
            // Note: This condition handles NaN because NaN is not equal to any other
            // value, including itself.
            if (mTemporaryScreenAutoBrightnessAdjustmentSettingOverride != adj) {
                mTemporaryScreenAutoBrightnessAdjustmentSettingOverride = adj;
                mDirty |= DIRTY_SETTINGS;
                updatePowerStateLocked();
            }
        }
    }

    /**
     * Low-level function turn the device off immediately, without trying
     * to be clean.  Most people should use {@link ShutdownThread} for a clean shutdown.
     */
    public static void lowLevelShutdown() {
        nativeShutdown();
    }

    /**
     * Low-level function to reboot the device.
     *
     * @param reason code to pass to the kernel (e.g. "recovery"), or null.
     * @throws IOException if reboot fails for some reason (eg, lack of
     *         permission)
     */
    public static void lowLevelReboot(String reason) throws IOException {
        nativeReboot(reason);
    }

    @Override // Watchdog.Monitor implementation
    public void monitor() {
        // Grab and release lock for watchdog monitor to detect deadlocks.
        synchronized (mLock) {
        }
    }

    @Override // Binder call
    protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
        if (mContext.checkCallingOrSelfPermission(Manifest.permission.DUMP)
                != PackageManager.PERMISSION_GRANTED) {
            pw.println("Permission Denial: can't dump PowerManager from from pid="
                    + Binder.getCallingPid()
                    + ", uid=" + Binder.getCallingUid());
            return;
        }

        pw.println("POWER MANAGER (dumpsys power)\n");

        final DisplayPowerController dpc;
        synchronized (mLock) {
            pw.println("Power Manager State:");
            pw.println("  mDirty=0x" + Integer.toHexString(mDirty));
            pw.println("  mWakefulness=" + wakefulnessToString(mWakefulness));
            pw.println("  mIsPowered=" + mIsPowered);
            pw.println("  mPlugType=" + mPlugType);
            pw.println("  mStayOn=" + mStayOn);
            pw.println("  mBootCompleted=" + mBootCompleted);
            pw.println("  mSystemReady=" + mSystemReady);
            pw.println("  mWakeLockSummary=0x" + Integer.toHexString(mWakeLockSummary));
            pw.println("  mUserActivitySummary=0x" + Integer.toHexString(mUserActivitySummary));
            pw.println("  mRequestWaitForNegativeProximity=" + mRequestWaitForNegativeProximity);
            pw.println("  mSandmanScheduled=" + mSandmanScheduled);
            pw.println("  mLastWakeTime=" + TimeUtils.formatUptime(mLastWakeTime));
            pw.println("  mLastSleepTime=" + TimeUtils.formatUptime(mLastSleepTime));
            pw.println("  mSendWakeUpFinishedNotificationWhenReady="
                    + mSendWakeUpFinishedNotificationWhenReady);
            pw.println("  mSendGoToSleepFinishedNotificationWhenReady="
                    + mSendGoToSleepFinishedNotificationWhenReady);
            pw.println("  mLastUserActivityTime=" + TimeUtils.formatUptime(mLastUserActivityTime));
            pw.println("  mLastUserActivityTimeNoChangeLights="
                    + TimeUtils.formatUptime(mLastUserActivityTimeNoChangeLights));
            pw.println("  mDisplayReady=" + mDisplayReady);
            pw.println("  mHoldingWakeLockSuspendBlocker=" + mHoldingWakeLockSuspendBlocker);

            pw.println();
            pw.println("Settings and Configuration:");
            pw.println("  mDreamsSupportedConfig=" + mDreamsSupportedConfig);
            pw.println("  mDreamsEnabledSetting=" + mDreamsEnabledSetting);
            pw.println("  mDreamsActivateOnSleepSetting=" + mDreamsActivateOnSleepSetting);
            pw.println("  mScreenOffTimeoutSetting=" + mScreenOffTimeoutSetting);
            pw.println("  mMaximumScreenOffTimeoutFromDeviceAdmin="
                    + mMaximumScreenOffTimeoutFromDeviceAdmin + " (enforced="
                    + isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked() + ")");
            pw.println("  mStayOnWhilePluggedInSetting=" + mStayOnWhilePluggedInSetting);
            pw.println("  mScreenBrightnessSetting=" + mScreenBrightnessSetting);
            pw.println("  mScreenAutoBrightnessAdjustmentSetting="
                    + mScreenAutoBrightnessAdjustmentSetting);
            pw.println("  mScreenBrightnessModeSetting=" + mScreenBrightnessModeSetting);
            pw.println("  mScreenBrightnessOverrideFromWindowManager="
                    + mScreenBrightnessOverrideFromWindowManager);
            pw.println("  mUserActivityTimeoutOverrideFromWindowManager="
                    + mUserActivityTimeoutOverrideFromWindowManager);
            pw.println("  mTemporaryScreenBrightnessSettingOverride="
                    + mTemporaryScreenBrightnessSettingOverride);
            pw.println("  mTemporaryScreenAutoBrightnessAdjustmentSettingOverride="
                    + mTemporaryScreenAutoBrightnessAdjustmentSettingOverride);
            pw.println("  mScreenBrightnessSettingMinimum=" + mScreenBrightnessSettingMinimum);
            pw.println("  mScreenBrightnessSettingMaximum=" + mScreenBrightnessSettingMaximum);
            pw.println("  mScreenBrightnessSettingDefault=" + mScreenBrightnessSettingDefault);

            final int screenOffTimeout = getScreenOffTimeoutLocked();
            final int screenDimDuration = getScreenDimDurationLocked(screenOffTimeout);
            pw.println();
            pw.println("Screen off timeout: " + screenOffTimeout + " ms");
            pw.println("Screen dim duration: " + screenDimDuration + " ms");

            pw.println();
            pw.println("Wake Locks: size=" + mWakeLocks.size());
            for (WakeLock wl : mWakeLocks) {
                pw.println("  " + wl);
            }

            pw.println();
            pw.println("Suspend Blockers: size=" + mSuspendBlockers.size());
            for (SuspendBlocker sb : mSuspendBlockers) {
                pw.println("  " + sb);
            }

            dpc = mDisplayPowerController;
        }

        if (dpc != null) {
            dpc.dump(pw);
        }
    }

    private SuspendBlocker createSuspendBlockerLocked(String name) {
        SuspendBlocker suspendBlocker = new SuspendBlockerImpl(name);
        mSuspendBlockers.add(suspendBlocker);
        return suspendBlocker;
    }

    private static String wakefulnessToString(int wakefulness) {
        switch (wakefulness) {
            case WAKEFULNESS_ASLEEP:
                return "Asleep";
            case WAKEFULNESS_AWAKE:
                return "Awake";
            case WAKEFULNESS_DREAMING:
                return "Dreaming";
            case WAKEFULNESS_NAPPING:
                return "Napping";
            default:
                return Integer.toString(wakefulness);
        }
    }

    private static WorkSource copyWorkSource(WorkSource workSource) {
        return workSource != null ? new WorkSource(workSource) : null;
    }

    private final class BatteryReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            synchronized (mLock) {
                handleBatteryStateChangedLocked();
            }
        }
    }

    private final class BootCompletedReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            synchronized (mLock) {
                handleBootCompletedLocked();
            }
        }
    }

    private final class DreamReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            synchronized (mLock) {
                scheduleSandmanLocked();
            }
        }
    }

    private final class UserSwitchedReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            synchronized (mLock) {
                handleSettingsChangedLocked();
            }
        }
    }

    private final class SettingsObserver extends ContentObserver {
        public SettingsObserver(Handler handler) {
            super(handler);
        }

        @Override
        public void onChange(boolean selfChange, Uri uri) {
            synchronized (mLock) {
                handleSettingsChangedLocked();
            }
        }
    }

    private final WindowManagerPolicy.ScreenOnListener mScreenOnListener =
            new WindowManagerPolicy.ScreenOnListener() {
        @Override
        public void onScreenOn() {
        }
    };

    /**
     * Handler for asynchronous operations performed by the power manager.
     */
    private final class PowerManagerHandler extends Handler {
        public PowerManagerHandler(Looper looper) {
            super(looper, null, true /*async*/);
        }

        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MSG_USER_ACTIVITY_TIMEOUT:
                    handleUserActivityTimeout();
                    break;
                case MSG_SANDMAN:
                    handleSandman();
                    break;
            }
        }
    }

    /**
     * Represents a wake lock that has been acquired by an application.
     */
    private final class WakeLock implements IBinder.DeathRecipient {
        public final IBinder mLock;
        public int mFlags;
        public String mTag;
        public WorkSource mWorkSource;
        public int mOwnerUid;
        public int mOwnerPid;

        public WakeLock(IBinder lock, int flags, String tag, WorkSource workSource,
                int ownerUid, int ownerPid) {
            mLock = lock;
            mFlags = flags;
            mTag = tag;
            mWorkSource = copyWorkSource(workSource);
            mOwnerUid = ownerUid;
            mOwnerPid = ownerPid;
        }

        @Override
        public void binderDied() {
            PowerManagerService.this.handleWakeLockDeath(this);
        }

        public boolean hasSameProperties(int flags, String tag, WorkSource workSource,
                int ownerUid, int ownerPid) {
            return mFlags == flags
                    && mTag.equals(tag)
                    && hasSameWorkSource(workSource)
                    && mOwnerUid == ownerUid
                    && mOwnerPid == ownerPid;
        }

        public void updateProperties(int flags, String tag, WorkSource workSource,
                int ownerUid, int ownerPid) {
            mFlags = flags;
            mTag = tag;
            updateWorkSource(workSource);
            mOwnerUid = ownerUid;
            mOwnerPid = ownerPid;
        }

        public boolean hasSameWorkSource(WorkSource workSource) {
            return Objects.equal(mWorkSource, workSource);
        }

        public void updateWorkSource(WorkSource workSource) {
            mWorkSource = copyWorkSource(workSource);
        }

        @Override
        public String toString() {
            return getLockLevelString()
                    + " '" + mTag + "'" + getLockFlagsString()
                    + " (uid=" + mOwnerUid + ", pid=" + mOwnerPid + ", ws=" + mWorkSource + ")";
        }

        private String getLockLevelString() {
            switch (mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
                case PowerManager.FULL_WAKE_LOCK:
                    return "FULL_WAKE_LOCK                ";
                case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
                    return "SCREEN_BRIGHT_WAKE_LOCK       ";
                case PowerManager.SCREEN_DIM_WAKE_LOCK:
                    return "SCREEN_DIM_WAKE_LOCK          ";
                case PowerManager.PARTIAL_WAKE_LOCK:
                    return "PARTIAL_WAKE_LOCK             ";
                case PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK:
                    return "PROXIMITY_SCREEN_OFF_WAKE_LOCK";
                default:
                    return "???                           ";
            }
        }

        private String getLockFlagsString() {
            String result = "";
            if ((mFlags & PowerManager.ACQUIRE_CAUSES_WAKEUP) != 0) {
                result += " ACQUIRE_CAUSES_WAKEUP";
            }
            if ((mFlags & PowerManager.ON_AFTER_RELEASE) != 0) {
                result += " ON_AFTER_RELEASE";
            }
            return result;
        }
    }

    private final class SuspendBlockerImpl implements SuspendBlocker {
        private final String mName;
        private int mReferenceCount;

        public SuspendBlockerImpl(String name) {
            mName = name;
        }

        @Override
        protected void finalize() throws Throwable {
            try {
                if (mReferenceCount != 0) {
                    Log.wtf(TAG, "Suspend blocker \"" + mName
                            + "\" was finalized without being released!");
                    mReferenceCount = 0;
                    nativeReleaseSuspendBlocker(mName);
                }
            } finally {
                super.finalize();
            }
        }

        @Override
        public void acquire() {
            synchronized (this) {
                mReferenceCount += 1;
                if (mReferenceCount == 1) {
                    nativeAcquireSuspendBlocker(mName);
                }
            }
        }

        @Override
        public void release() {
            synchronized (this) {
                mReferenceCount -= 1;
                if (mReferenceCount == 0) {
                    nativeReleaseSuspendBlocker(mName);
                } else if (mReferenceCount < 0) {
                    Log.wtf(TAG, "Suspend blocker \"" + mName
                            + "\" was released without being acquired!", new Throwable());
                    mReferenceCount = 0;
                }
            }
        }

        @Override
        public String toString() {
            synchronized (this) {
                return mName + ": ref count=" + mReferenceCount;
            }
        }
    }
}