Revert "DisplayEventDispatcher: optimize binder calls"

This reverts commit 981787535c543cf82ef6f92ad17e9d15b6dc032f.

Reason for revert: b/179721483

Change-Id: I667bbcdb6cc8c06624d6dbb599aa612b0af24951

3 files changed, 22 insertions, 67 deletions

diff --git a/libs/gui/DisplayEventDispatcher.cpp b/libs/gui/DisplayEventDispatcher.cpp
index 2ad484add3..c6c9a8f7a7 100644
--- a/libs/gui/DisplayEventDispatcher.cpp
+++ b/libs/gui/DisplayEventDispatcher.cpp
@@ -36,9 +36,7 @@ static const size_t EVENT_BUFFER_SIZE = 100;
 DisplayEventDispatcher::DisplayEventDispatcher(
         const sp<Looper>& looper, ISurfaceComposer::VsyncSource vsyncSource,
         ISurfaceComposer::EventRegistrationFlags eventRegistration)
-      : mLooper(looper),
-        mReceiver(vsyncSource, eventRegistration),
-        mVsyncState(VsyncState::Unregistered) {
+      : mLooper(looper), mReceiver(vsyncSource, eventRegistration), mWaitingForVsync(false) {
     ALOGV("dispatcher %p ~ Initializing display event dispatcher.", this);
 }
 
@@ -68,37 +66,26 @@ void DisplayEventDispatcher::dispose() {
 }
 
 status_t DisplayEventDispatcher::scheduleVsync() {
-    switch (mVsyncState) {
-        case VsyncState::Unregistered: {
-            ALOGV("dispatcher %p ~ Scheduling vsync.", this);
-
-            // Drain all pending events.
-            nsecs_t vsyncTimestamp;
-            PhysicalDisplayId vsyncDisplayId;
-            uint32_t vsyncCount;
-            VsyncEventData vsyncEventData;
-            if (processPendingEvents(&vsyncTimestamp, &vsyncDisplayId, &vsyncCount,
-                                     &vsyncEventData)) {
-                ALOGE("dispatcher %p ~ last event processed while scheduling was for %" PRId64 "",
-                      this, ns2ms(static_cast<nsecs_t>(vsyncTimestamp)));
-            }
-
-            status_t status = mReceiver.setVsyncRate(1);
-            if (status) {
-                ALOGW("Failed to set vsync rate, status=%d", status);
-                return status;
-            }
-
-            mVsyncState = VsyncState::RegisteredAndWaitingForVsync;
-            break;
+    if (!mWaitingForVsync) {
+        ALOGV("dispatcher %p ~ Scheduling vsync.", this);
+
+        // Drain all pending events.
+        nsecs_t vsyncTimestamp;
+        PhysicalDisplayId vsyncDisplayId;
+        uint32_t vsyncCount;
+        VsyncEventData vsyncEventData;
+        if (processPendingEvents(&vsyncTimestamp, &vsyncDisplayId, &vsyncCount, &vsyncEventData)) {
+            ALOGE("dispatcher %p ~ last event processed while scheduling was for %" PRId64 "", this,
+                  ns2ms(static_cast<nsecs_t>(vsyncTimestamp)));
         }
-        case VsyncState::Registered: {
-            mVsyncState = VsyncState::RegisteredAndWaitingForVsync;
-            break;
-        }
-        case VsyncState::RegisteredAndWaitingForVsync: {
-            break;
+
+        status_t status = mReceiver.requestNextVsync();
+        if (status) {
+            ALOGW("Failed to request next vsync, status=%d", status);
+            return status;
         }
+
+        mWaitingForVsync = true;
     }
     return OK;
 }
@@ -136,23 +123,8 @@ int DisplayEventDispatcher::handleEvent(int, int events, void*) {
               ", displayId=%s, count=%d, vsyncId=%" PRId64,
               this, ns2ms(vsyncTimestamp), to_string(vsyncDisplayId).c_str(), vsyncCount,
               vsyncEventData.id);
-        switch (mVsyncState) {
-            case VsyncState::Unregistered:
-                ALOGW("Received unexpected VSYNC event");
-                break;
-            case VsyncState::RegisteredAndWaitingForVsync:
-                mVsyncState = VsyncState::Registered;
-                dispatchVsync(vsyncTimestamp, vsyncDisplayId, vsyncCount, vsyncEventData);
-                break;
-            case VsyncState::Registered:
-                status_t status = mReceiver.setVsyncRate(0);
-                if (status) {
-                    ALOGW("Failed to reset vsync rate, status=%d", status);
-                    return status;
-                }
-                mVsyncState = VsyncState::Unregistered;
-                break;
-        }
+        mWaitingForVsync = false;
+        dispatchVsync(vsyncTimestamp, vsyncDisplayId, vsyncCount, vsyncEventData);
     }
 
     return 1; // keep the callback
diff --git a/libs/gui/include/gui/DisplayEventDispatcher.h b/libs/gui/include/gui/DisplayEventDispatcher.h
index 4c2b08b2bb..5587acf08f 100644
--- a/libs/gui/include/gui/DisplayEventDispatcher.h
+++ b/libs/gui/include/gui/DisplayEventDispatcher.h
@@ -52,20 +52,7 @@ protected:
 private:
     sp<Looper> mLooper;
     DisplayEventReceiver mReceiver;
-    // The state of vsync event registration and whether the client is expecting
-    // an event or not.
-    enum class VsyncState {
-        // The dispatcher is not registered for vsync events.
-        Unregistered,
-        // The dispatcher is registered to receive vsync events but should not dispatch it to the
-        // client as the client is not expecting a vsync event.
-        Registered,
-
-        // The dispatcher is registered to receive vsync events and supposed to dispatch it to
-        // the client.
-        RegisteredAndWaitingForVsync,
-    };
-    VsyncState mVsyncState;
+    bool mWaitingForVsync;
 
     std::vector<FrameRateOverride> mFrameRateOverrides;
 
diff --git a/services/surfaceflinger/Scheduler/EventThread.cpp b/services/surfaceflinger/Scheduler/EventThread.cpp
index f90c130992..c12a7b106a 100644
--- a/services/surfaceflinger/Scheduler/EventThread.cpp
+++ b/services/surfaceflinger/Scheduler/EventThread.cpp
@@ -303,10 +303,6 @@ void EventThread::setVsyncRate(uint32_t rate, const sp<EventThreadConnection>& c
     std::lock_guard<std::mutex> lock(mMutex);
 
     const auto request = rate == 0 ? VSyncRequest::None : static_cast<VSyncRequest>(rate);
-    if (request != VSyncRequest::None && connection->resyncCallback) {
-        connection->resyncCallback();
-    }
-
     if (connection->vsyncRequest != request) {
         connection->vsyncRequest = request;
         mCondition.notify_all();