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Commit 20f87d7a authored by Mike Lockwood's avatar Mike Lockwood
Browse files

Throttle proximity sensor values so we do not process more than one change a second. 



This is to prevent a noisy proximity sensor from causing the screen to turn on and off
in rapid succession, which can trigger race conditions in the keyguard manager.

Change-Id: I2c6e54e4b41716e038854ed9a827c901579c8865
Signed-off-by: default avatarMike Lockwood <lockwood@android.com>
parent 67b69292

services/java/com/android/server/PowerManagerService.java

+49 −15
Original line number Diff line number Diff line
@@ -93,6 +93,9 @@ class PowerManagerService extends IPowerManager.Stub 
    // How long to wait to debounce light sensor changes.

    private static final int LIGHT_SENSOR_DELAY = 1000;



    // For debouncing the proximity sensor.

    private static final int PROXIMITY_SENSOR_DELAY = 1000;



    // trigger proximity if distance is less than 5 cm

    private static final float PROXIMITY_THRESHOLD = 5.0f;
@@ -162,6 +165,8 @@ class PowerManagerService extends IPowerManager.Stub 
    private boolean mKeyboardVisible = false;

    private boolean mUserActivityAllowed = true;

    private boolean mProximitySensorActive = false;

    private int mProximityPendingValue = -1; // -1 == nothing, 0 == inactive, 1 == active

    private long mLastProximityEventTime;

    private int mTotalDelaySetting;

    private int mKeylightDelay;

    private int mDimDelay;
@@ -886,6 +891,8 @@ class PowerManagerService extends IPowerManager.Stub 
        pw.println("  mStayOnWhilePluggedInPartialLock=" + mStayOnWhilePluggedInPartialLock);

        pw.println("  mPreventScreenOnPartialLock=" + mPreventScreenOnPartialLock);

        pw.println("  mProximitySensorActive=" + mProximitySensorActive);

        pw.println("  mProximityPendingValue=" + mProximityPendingValue);

        pw.println("  mLastProximityEventTime=" + mLastProximityEventTime);

        pw.println("  mLightSensorEnabled=" + mLightSensorEnabled);

        pw.println("  mLightSensorValue=" + mLightSensorValue);

        pw.println("  mLightSensorPendingValue=" + mLightSensorPendingValue);
@@ -1895,6 +1902,17 @@ class PowerManagerService extends IPowerManager.Stub 
        }

    }



    private Runnable mProximityTask = new Runnable() {

        public void run() {

            synchronized (mLocks) {

                if (mProximityPendingValue != -1) {

                    proximityChangedLocked(mProximityPendingValue == 1);

                    mProximityPendingValue = -1;

                }

            }

        }

    };



    private Runnable mAutoBrightnessTask = new Runnable() {

        public void run() {

            synchronized (mLocks) {
@@ -2327,6 +2345,7 @@ class PowerManagerService extends IPowerManager.Stub 
        long identity = Binder.clearCallingIdentity();

        try {

            mSensorManager.unregisterListener(mProximityListener);

            mHandler.removeCallbacks(mProximityTask);

        } finally {

            Binder.restoreCallingIdentity(identity);

        }
@@ -2338,6 +2357,22 @@ class PowerManagerService extends IPowerManager.Stub 
        }

    }



    private void proximityChangedLocked(boolean active) {

        if (mSpew) {

            Log.d(TAG, "proximityChangedLocked, active: " + active);

        }

        if (active) {

            goToSleepLocked(SystemClock.uptimeMillis());

            mProximitySensorActive = true;

        } else {

            // proximity sensor negative events trigger as user activity.

            // temporarily set mUserActivityAllowed to true so this will work

            // even when the keyguard is on.

            mProximitySensorActive = false;

            forceUserActivityLocked();

        }

    }



    private void enableLightSensor(boolean enable) {

        if (mDebugLightSensor) {

            Log.d(TAG, "enableLightSensor " + enable);
@@ -2365,23 +2400,22 @@ class PowerManagerService extends IPowerManager.Stub 
            long milliseconds = event.timestamp / 1000000;

            synchronized (mLocks) {

                float distance = event.values[0];

                long timeSinceLastEvent = milliseconds - mLastProximityEventTime;

                mLastProximityEventTime = milliseconds;

                mHandler.removeCallbacks(mProximityTask);



                // compare against getMaximumRange to support sensors that only return 0 or 1

                if (distance >= 0.0 && distance < PROXIMITY_THRESHOLD &&

                        distance < mProximitySensor.getMaximumRange()) {

                    if (mSpew) {

                        Log.d(TAG, "onSensorChanged: proximity active, distance: " + distance);

                    }

                    goToSleepLocked(milliseconds);

                    mProximitySensorActive = true;

                boolean active = (distance >= 0.0 && distance < PROXIMITY_THRESHOLD &&

                        distance < mProximitySensor.getMaximumRange());



                if (timeSinceLastEvent < PROXIMITY_SENSOR_DELAY) {

                    // enforce delaying atleast PROXIMITY_SENSOR_DELAY before processing

                    mProximityPendingValue = (active ? 1 : 0);

                    mHandler.postDelayed(mProximityTask, PROXIMITY_SENSOR_DELAY - timeSinceLastEvent);

                } else {

                    // proximity sensor negative events trigger as user activity.

                    // temporarily set mUserActivityAllowed to true so this will work

                    // even when the keyguard is on.

                    if (mSpew) {

                        Log.d(TAG, "onSensorChanged: proximity inactive, distance: " + distance);

                    }

                    mProximitySensorActive = false;

                    forceUserActivityLocked();

                    // process the value immediately

                    mProximityPendingValue = -1;

                    proximityChangedLocked(active);

                }

            }

        }