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Commit 85cc1844 authored by Riddle Hsu's avatar Riddle Hsu
Browse files

Avoid race of checking screen states and sleep token 

The callback *GoingToSleep and screenTurn* run on different threads,
so there could be a race if screen on/off in a short time and the
thread has some delays:
Thread1 gets isScreenOnEarly==false
Thread2 modifies isScreenOnEarly=true
Thread2 releases sleep-token
Thread1 acquire sleep-token
Then the final state is screen on but sleep-token is still acquired.

This change moves the fail-safe check from startedGoingToSleep
to finishedGoingToSleep>setAwake(false) and reuse the existing
SleepTokenAcquirer, so it is easier to acquire/release in
DisplayPolicy inside a lock. Now the check of isScreenOnEarly and
sleep-token in screenTurningOn and setAwake are synchronized.

Bug: 364760760
Flag: EXEMPT bugfix
Test: PhoneWindowManagerTests
Change-Id: I5c47b4a745fcd369d3ec825c41a7c1d35ce9feca
parent 2f4e0476

services/core/java/com/android/server/policy/PhoneWindowManager.java

+3 −26
Original line number Diff line number Diff line
@@ -529,7 +529,7 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
    volatile boolean mRequestedOrSleepingDefaultDisplay;



    /**

     * This is used to check whether to invoke {@link #updateScreenOffSleepToken} when screen is

     * This is used to check whether to acquire screen-off sleep token when screen is

     * turned off. E.g. if it is false when screen is turned off and the display is swapping, it

     * is expected that the screen will be on in a short time. Then it is unnecessary to acquire

     * screen-off-sleep-token, so it can avoid intermediate visibility or lifecycle changes.
@@ -604,7 +604,6 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
    private boolean mPendingKeyguardOccluded;

    private boolean mKeyguardOccludedChanged;



    private ActivityTaskManagerInternal.SleepTokenAcquirer mScreenOffSleepTokenAcquirer;

    Intent mHomeIntent;

    Intent mCarDockIntent;

    Intent mDeskDockIntent;
@@ -2217,9 +2216,6 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
        mLockPatternUtils = new LockPatternUtils(mContext);

        mLogger = new MetricsLogger();



        mScreenOffSleepTokenAcquirer = mActivityTaskManagerInternal

                .createSleepTokenAcquirer("ScreenOff");



        Resources res = mContext.getResources();

        mWakeOnDpadKeyPress =

                res.getBoolean(com.android.internal.R.bool.config_wakeOnDpadKeyPress);
@@ -5526,13 +5522,6 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
        mRequestedOrSleepingDefaultDisplay = true;

        mIsGoingToSleepDefaultDisplay = true;



        // In case startedGoingToSleep is called after screenTurnedOff (the source caller is in

        // order but the methods run on different threads) and updateScreenOffSleepToken was

        // skipped. Then acquire sleep token if screen was off.

        if (!mDefaultDisplayPolicy.isScreenOnFully() && !mDefaultDisplayPolicy.isScreenOnEarly()) {

            updateScreenOffSleepToken(true /* acquire */);

        }



        if (mKeyguardDelegate != null) {

            mKeyguardDelegate.onStartedGoingToSleep(pmSleepReason);

        }
@@ -5693,11 +5682,9 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
        if (DEBUG_WAKEUP) Slog.i(TAG, "Display" + displayId + " turned off...");



        if (displayId == DEFAULT_DISPLAY) {

            if (!isSwappingDisplay || mIsGoingToSleepDefaultDisplay) {

                updateScreenOffSleepToken(true /* acquire */);

            }

            final boolean acquireSleepToken = !isSwappingDisplay || mIsGoingToSleepDefaultDisplay;

            mRequestedOrSleepingDefaultDisplay = false;

            mDefaultDisplayPolicy.screenTurnedOff();

            mDefaultDisplayPolicy.screenTurnedOff(acquireSleepToken);

            synchronized (mLock) {

                if (mKeyguardDelegate != null) {

                    mKeyguardDelegate.onScreenTurnedOff();
@@ -5753,7 +5740,6 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
        if (displayId == DEFAULT_DISPLAY) {

            Trace.asyncTraceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "screenTurningOn",

                    0 /* cookie */);

            updateScreenOffSleepToken(false /* acquire */);

            mDefaultDisplayPolicy.screenTurningOn(screenOnListener);

            mBootAnimationDismissable = false;
@@ -6260,15 +6246,6 @@ public class PhoneWindowManager implements WindowManagerPolicy { 
        }

    }



    // TODO (multidisplay): Support multiple displays in WindowManagerPolicy.

    private void updateScreenOffSleepToken(boolean acquire) {

        if (acquire) {

            mScreenOffSleepTokenAcquirer.acquire(DEFAULT_DISPLAY);

        } else {

            mScreenOffSleepTokenAcquirer.release(DEFAULT_DISPLAY);

        }

    }



    /** {@inheritDoc} */

    @Override

    public void enableScreenAfterBoot() {

services/core/java/com/android/server/wm/ActivityTaskManagerInternal.java

+0 −29
Original line number Diff line number Diff line
@@ -129,35 +129,6 @@ public abstract class ActivityTaskManagerInternal { 
        void onKeyguardStateChanged(boolean isShowing);

    }



    /**

     * Sleep tokens cause the activity manager to put the top activity to sleep.

     * They are used by components such as dreams that may hide and block interaction

     * with underlying activities.

     * The Acquirer provides an interface that encapsulates the underlying work, so the user does

     * not need to handle the token by him/herself.

     */

    public interface SleepTokenAcquirer {



        /**

         * Acquires a sleep token.

         * @param displayId The display to apply to.

         */

        void acquire(int displayId);



        /**

         * Releases the sleep token.

         * @param displayId The display to apply to.

         */

        void release(int displayId);

    }



    /**

     * Creates a sleep token acquirer for the specified display with the specified tag.

     *

     * @param tag A string identifying the purpose (eg. "Dream").

     */

    public abstract SleepTokenAcquirer createSleepTokenAcquirer(@NonNull String tag);



    /**

     * Returns home activity for the specified user.

     *

services/core/java/com/android/server/wm/ActivityTaskManagerService.java

+5 −11
Original line number Diff line number Diff line
@@ -4349,6 +4349,7 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub { 
            mTaskOrganizerController.dump(pw, "  ");

            mVisibleActivityProcessTracker.dump(pw, "  ");

            mActiveUids.dump(pw, "  ");

            pw.println("  SleepTokens=" + mRootWindowContainer.mSleepTokens);

            if (mDemoteTopAppReasons != 0) {

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

            }
@@ -5064,17 +5065,16 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub { 
        EventLogTags.writeWmSetResumedActivity(r.mUserId, r.shortComponentName, reason);

    }



    final class SleepTokenAcquirerImpl implements ActivityTaskManagerInternal.SleepTokenAcquirer {

    final class SleepTokenAcquirer {

        private final String mTag;

        private final SparseArray<RootWindowContainer.SleepToken> mSleepTokens =

                new SparseArray<>();



        SleepTokenAcquirerImpl(@NonNull String tag) {

        SleepTokenAcquirer(@NonNull String tag) {

            mTag = tag;

        }



        @Override

        public void acquire(int displayId) {

        void acquire(int displayId) {

            synchronized (mGlobalLock) {

                if (!mSleepTokens.contains(displayId)) {

                    mSleepTokens.append(displayId,
@@ -5084,8 +5084,7 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub { 
            }

        }



        @Override

        public void release(int displayId) {

        void release(int displayId) {

            synchronized (mGlobalLock) {

                final RootWindowContainer.SleepToken token = mSleepTokens.get(displayId);

                if (token != null) {
@@ -5948,11 +5947,6 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub { 
    }



    final class LocalService extends ActivityTaskManagerInternal {

        @Override

        public SleepTokenAcquirer createSleepTokenAcquirer(@NonNull String tag) {

            Objects.requireNonNull(tag);

            return new SleepTokenAcquirerImpl(tag);

        }



        @Override

        public ComponentName getHomeActivityForUser(int userId) {

services/core/java/com/android/server/wm/DisplayContent.java

+2 −5
Original line number Diff line number Diff line
@@ -738,8 +738,6 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp 


    /** All tokens used to put activities on this root task to sleep (including mOffToken) */

    final ArrayList<RootWindowContainer.SleepToken> mAllSleepTokens = new ArrayList<>();

    /** The token acquirer to put root tasks on the display to sleep */

    private final ActivityTaskManagerInternal.SleepTokenAcquirer mOffTokenAcquirer;



    private boolean mSleeping;
@@ -1134,7 +1132,6 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp 
        mDisplay = display;

        mDisplayId = display.getDisplayId();

        mCurrentUniqueDisplayId = display.getUniqueId();

        mOffTokenAcquirer = mRootWindowContainer.mDisplayOffTokenAcquirer;

        mWallpaperController = new WallpaperController(mWmService, this);

        mWallpaperController.resetLargestDisplay(display);

        display.getDisplayInfo(mDisplayInfo);
@@ -6167,9 +6164,9 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp 
        final int displayState = mDisplayInfo.state;

        if (displayId != DEFAULT_DISPLAY) {

            if (displayState == Display.STATE_OFF) {

                mOffTokenAcquirer.acquire(mDisplayId);

                mRootWindowContainer.mDisplayOffTokenAcquirer.acquire(mDisplayId);

            } else if (displayState == Display.STATE_ON) {

                mOffTokenAcquirer.release(mDisplayId);

                mRootWindowContainer.mDisplayOffTokenAcquirer.release(mDisplayId);

            }

            ProtoLog.v(WM_DEBUG_CONTENT_RECORDING,

                    "Content Recording: Display %d state was (%d), is now (%d), so update "

services/core/java/com/android/server/wm/DisplayPolicy.java

+14 −1
Original line number Diff line number Diff line
@@ -804,6 +804,14 @@ public class DisplayPolicy { 
                    mAwake /* waiting */);

            if (!awake) {

                onDisplaySwitchFinished();

                // In case PhoneWindowManager's startedGoingToSleep is called after screenTurnedOff

                // (the source caller is in order but the methods run on different threads) and

                // updateScreenOffSleepToken was skipped by mIsGoingToSleepDefaultDisplay. Then

                // acquire sleep token if screen is off.

                if (!mScreenOnEarly && !mScreenOnFully && !mDisplayContent.isSleeping()) {

                    Slog.w(TAG, "Late acquire sleep token for " + mDisplayContent);

                    mService.mRoot.mDisplayOffTokenAcquirer.acquire(mDisplayContent.mDisplayId);

                }

            }

        }

    }
@@ -851,6 +859,7 @@ public class DisplayPolicy { 
    public void screenTurningOn(ScreenOnListener screenOnListener) {

        WindowProcessController visibleDozeUiProcess = null;

        synchronized (mLock) {

            mService.mRoot.mDisplayOffTokenAcquirer.release(mDisplayContent.mDisplayId);

            mScreenOnEarly = true;

            mScreenOnFully = false;

            mKeyguardDrawComplete = false;
@@ -875,8 +884,12 @@ public class DisplayPolicy { 
        onDisplaySwitchFinished();

    }



    public void screenTurnedOff() {

    /** It is called after {@link #screenTurningOn}. This runs on PowerManager's thread. */

    public void screenTurnedOff(boolean acquireSleepToken) {

        synchronized (mLock) {

            if (acquireSleepToken) {

                mService.mRoot.mDisplayOffTokenAcquirer.acquire(mDisplayContent.mDisplayId);

            }

            mScreenOnEarly = false;

            mScreenOnFully = false;

            mKeyguardDrawComplete = false;