services/surfaceflinger/EventControlThread.cpp

/*
 * Copyright (C) 2013 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.
 */

#include "EventControlThread.h"
#include "SurfaceFlinger.h"

namespace android {

EventControlThread::EventControlThread(const sp<SurfaceFlinger>& flinger):
        mFlinger(flinger),
        mVsyncEnabled(false) {
}

void EventControlThread::setVsyncEnabled(bool enabled) {
    Mutex::Autolock lock(mMutex);
    mVsyncEnabled = enabled;
    mCond.signal();
}

bool EventControlThread::threadLoop() {
    Mutex::Autolock lock(mMutex);

    bool vsyncEnabled = mVsyncEnabled;

    mFlinger->eventControl(HWC_DISPLAY_PRIMARY, SurfaceFlinger::EVENT_VSYNC,
            mVsyncEnabled);

    while (true) {
        status_t err = mCond.wait(mMutex);
        if (err != NO_ERROR) {
            ALOGE("error waiting for new events: %s (%d)",
                strerror(-err), err);
            return false;
        }

        if (vsyncEnabled != mVsyncEnabled) {
            mFlinger->eventControl(HWC_DISPLAY_PRIMARY,
                    SurfaceFlinger::EVENT_VSYNC, mVsyncEnabled);
            vsyncEnabled = mVsyncEnabled;
        }
    }

    return false;
}

} // namespace android