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Commit fc690e2a authored by Cheng Shi's avatar Cheng Shi
Browse files

Dispatch vsync when receiving vsync timeout to handle vsync loss. 



Currently we do not have a mechanism to guarantee the arrival of the vsync signal. The vsync signal loss may occur when the renderNodeAnimator is running. The render thread took a long time to perform drawing without time to read the pipe, and the pipe was filled with other signals like configChanged, causing surfaceflinger to miss a vsync signal.
If a vsync lost, causing DisplayEventDispatcher::mWaitingForVsync to be true, resulting in DisplayEventDispatcher::scheduleVsync can no longer schedule another vsync. So we need to dispatch vsync when receiving vsync timeout.

Bug: 204097701
Test: Manual
Change-Id: Ibfa7a301ea17ebd58cae6b790a61d66c3d2e43fd
Signed-off-by: default avatarshicheng <shicheng@xiaomi.com>
parent 5f852b9c

libs/gui/DisplayEventDispatcher.cpp

+17 −1
Original line number Diff line number Diff line
@@ -33,10 +33,13 @@ namespace android { 
// using just a few large reads.

static const size_t EVENT_BUFFER_SIZE = 100;



static constexpr nsecs_t WAITING_FOR_VSYNC_TIMEOUT = ms2ns(300);



DisplayEventDispatcher::DisplayEventDispatcher(

        const sp<Looper>& looper, ISurfaceComposer::VsyncSource vsyncSource,

        ISurfaceComposer::EventRegistrationFlags eventRegistration)

      : mLooper(looper), mReceiver(vsyncSource, eventRegistration), mWaitingForVsync(false) {

      : mLooper(looper), mReceiver(vsyncSource, eventRegistration), mWaitingForVsync(false),

        mLastVsyncCount(0), mLastScheduleVsyncTime(0) {

    ALOGV("dispatcher %p ~ Initializing display event dispatcher.", this);

}
@@ -86,6 +89,7 @@ status_t DisplayEventDispatcher::scheduleVsync() { 
        }



        mWaitingForVsync = true;

        mLastScheduleVsyncTime = systemTime(SYSTEM_TIME_MONOTONIC);

    }

    return OK;

}
@@ -124,9 +128,21 @@ int DisplayEventDispatcher::handleEvent(int, int events, void*) { 
              this, ns2ms(vsyncTimestamp), to_string(vsyncDisplayId).c_str(), vsyncCount,

              vsyncEventData.id);

        mWaitingForVsync = false;

        mLastVsyncCount = vsyncCount;

        dispatchVsync(vsyncTimestamp, vsyncDisplayId, vsyncCount, vsyncEventData);

    }



    if (mWaitingForVsync) {

        const nsecs_t currentTime = systemTime(SYSTEM_TIME_MONOTONIC);

        const nsecs_t vsyncScheduleDelay = currentTime - mLastScheduleVsyncTime;

        if (vsyncScheduleDelay > WAITING_FOR_VSYNC_TIMEOUT) {

            ALOGW("Vsync time out! vsyncScheduleDelay=%" PRId64 "ms", ns2ms(vsyncScheduleDelay));

            mWaitingForVsync = false;

            dispatchVsync(currentTime, vsyncDisplayId /* displayId is not used */,

                          ++mLastVsyncCount, vsyncEventData /* empty data */);

        }

    }



    return 1; // keep the callback

}

libs/gui/include/gui/DisplayEventDispatcher.h

+2 −0
Original line number Diff line number Diff line
@@ -56,6 +56,8 @@ private: 
    sp<Looper> mLooper;

    DisplayEventReceiver mReceiver;

    bool mWaitingForVsync;

    uint32_t mLastVsyncCount;

    nsecs_t mLastScheduleVsyncTime;



    std::vector<FrameRateOverride> mFrameRateOverrides;