Merge "Add timeout when waiting for HW vsync" into jb-mr1-dev

    return true;

}

// This will return when (1) a vsync event has been received, and (2) there was

// at least one connection interested in receiving it when we started waiting.

Vector< sp<EventThread::Connection> > EventThread::waitForEvent(

        DisplayEventReceiver::Event* event)

{

            // don't report it, and disable VSYNC events

            disableVSyncLocked();

        } else if (!timestamp && waitForVSync) {

            // we have at least one client, so we want vsync enabled

            // (TODO: this function is called right after we finish

            // notifying clients of a vsync, so this call will be made

            // at the vsync rate, e.g. 60fps.  If we can accurately

            // track the current state we could avoid making this call

            // so often.)

            enableVSyncLocked();

        }

        // note: !timestamp implies signalConnections.isEmpty()

        // note: !timestamp implies signalConnections.isEmpty(), because we

        // don't populate signalConnections if there's no vsync pending

        if (!timestamp) {

            // wait for something to happen

            if (CC_UNLIKELY(mUseSoftwareVSync && waitForVSync)) {

                // h/w vsync cannot be used (screen is off), so we use

                // a  timeout instead. it doesn't matter how imprecise this

                // is, we just need to make sure to serve the clients

                if (mCondition.waitRelative(mLock, ms2ns(16)) == TIMED_OUT) {

            if (waitForVSync) {

                // This is where we spend most of our time, waiting

                // for vsync events and new client registrations.

                //

                // If the screen is off, we can't use h/w vsync, so we

                // use a 16ms timeout instead.  It doesn't need to be

                // precise, we just need to keep feeding our clients.

                //

                // We don't want to stall if there's a driver bug, so we

                // use a (long) timeout when waiting for h/w vsync, and

                // generate fake events when necessary.

                bool softwareSync = mUseSoftwareVSync;

                nsecs_t timeout = softwareSync ? ms2ns(16) : ms2ns(1000);

                if (mCondition.waitRelative(mLock, timeout) == TIMED_OUT) {

                    if (!softwareSync) {

                        ALOGW("Timed out waiting for hw vsync; faking it");

                    }

                    mVSyncTimestamp = systemTime(SYSTEM_TIME_MONOTONIC);

                    mVSyncCount++;

                }

            } else {

                // This is where we spend most of our time, waiting

                // for a vsync events and registered clients

                // Nobody is interested in vsync, so we just want to sleep.

                // h/w vsync should be disabled, so this will wait until we

                // get a new connection, or an existing connection becomes

                // interested in receiving vsync again.

                mCondition.wait(mLock);

            }

        }

    } while (signalConnections.isEmpty());

    // here we're guaranteed to have a timestamp and some connections to signal

    // (The connections might have dropped out of mDisplayEventConnections

    // while we were asleep, but we'll still have strong references to them.)

    // dispatch vsync events to listeners...

    // fill in vsync event info

    event->header.type = DisplayEventReceiver::DISPLAY_EVENT_VSYNC;

    event->header.timestamp = timestamp;

    event->vsync.count = vsyncCount;