diff --git a/services/surfaceflinger/Scheduler/EventThread.cpp b/services/surfaceflinger/Scheduler/EventThread.cpp
index ff800c3..5bdef58 100644
--- a/services/surfaceflinger/Scheduler/EventThread.cpp
+++ b/services/surfaceflinger/Scheduler/EventThread.cpp
@@ -103,10 +103,11 @@
 }
 
 DisplayEventReceiver::Event makeConfigChanged(PhysicalDisplayId displayId,
-                                              HwcConfigIndexType configId) {
+                                              HwcConfigIndexType configId, nsecs_t vsyncPeriod) {
     DisplayEventReceiver::Event event;
     event.header = {DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED, displayId, systemTime()};
     event.config.configId = configId.value();
+    event.config.vsyncPeriod = vsyncPeriod;
     return event;
 }
 
@@ -116,7 +117,7 @@
                                              ResyncCallback resyncCallback,
                                              ISurfaceComposer::ConfigChanged configChanged)
       : resyncCallback(std::move(resyncCallback)),
-        configChanged(configChanged),
+        mConfigChanged(configChanged),
         mEventThread(eventThread),
         mChannel(gui::BitTube::DefaultSize) {}
 
@@ -145,6 +146,18 @@
     mEventThread->requestNextVsync(this);
 }
 
+void EventThreadConnection::toggleConfigEvents(ISurfaceComposer::ConfigChanged configChangeFlag) {
+    ATRACE_NAME("enableConfigEvents");
+    mConfigChanged = configChangeFlag;
+
+    // In principle it's possible for rapidly toggling config events to drop an
+    // event here, but it's unlikely in practice.
+    if (configChangeFlag == ISurfaceComposer::eConfigChangedDispatch) {
+        mForcedConfigChangeDispatch = true;
+        mEventThread->requestLatestConfig();
+    }
+}
+
 status_t EventThreadConnection::postEvent(const DisplayEventReceiver::Event& event) {
     ssize_t size = DisplayEventReceiver::sendEvents(&mChannel, &event, 1);
     return size < 0 ? status_t(size) : status_t(NO_ERROR);
@@ -257,6 +270,24 @@
     }
 }
 
+void EventThread::requestLatestConfig() {
+    std::lock_guard<std::mutex> lock(mMutex);
+    auto pendingConfigChange =
+            std::find_if(std::begin(mPendingEvents), std::end(mPendingEvents),
+                         [&](const DisplayEventReceiver::Event& event) {
+                             return event.header.type ==
+                                     DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED;
+                         });
+
+    // If we didn't find a pending config change event, then push out the
+    // latest one we've ever seen.
+    if (pendingConfigChange == std::end(mPendingEvents)) {
+        mPendingEvents.push_back(mLastConfigChangeEvent);
+    }
+
+    mCondition.notify_all();
+}
+
 void EventThread::onScreenReleased() {
     std::lock_guard<std::mutex> lock(mMutex);
     if (!mVSyncState || mVSyncState->synthetic) {
@@ -292,10 +323,11 @@
     mCondition.notify_all();
 }
 
-void EventThread::onConfigChanged(PhysicalDisplayId displayId, HwcConfigIndexType configId) {
+void EventThread::onConfigChanged(PhysicalDisplayId displayId, HwcConfigIndexType configId,
+                                  nsecs_t vsyncPeriod) {
     std::lock_guard<std::mutex> lock(mMutex);
 
-    mPendingEvents.push_back(makeConfigChanged(displayId, configId));
+    mPendingEvents.push_back(makeConfigChanged(displayId, configId, vsyncPeriod));
     mCondition.notify_all();
 }
 
@@ -325,6 +357,9 @@
                         mInterceptVSyncsCallback(event->header.timestamp);
                     }
                     break;
+                case DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED:
+                    mLastConfigChangeEvent = *event;
+                    break;
             }
         }
 
@@ -398,8 +433,11 @@
         case DisplayEventReceiver::DISPLAY_EVENT_HOTPLUG:
             return true;
 
-        case DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED:
-            return connection->configChanged == ISurfaceComposer::eConfigChangedDispatch;
+        case DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED: {
+            const bool forcedDispatch = connection->mForcedConfigChangeDispatch.exchange(false);
+            return forcedDispatch ||
+                    connection->mConfigChanged == ISurfaceComposer::eConfigChangedDispatch;
+        }
 
         case DisplayEventReceiver::DISPLAY_EVENT_VSYNC:
             switch (connection->vsyncRequest) {
diff --git a/services/surfaceflinger/Scheduler/EventThread.h b/services/surfaceflinger/Scheduler/EventThread.h
index a42546c..641b2a5 100644
--- a/services/surfaceflinger/Scheduler/EventThread.h
+++ b/services/surfaceflinger/Scheduler/EventThread.h
@@ -81,12 +81,19 @@
     status_t stealReceiveChannel(gui::BitTube* outChannel) override;
     status_t setVsyncRate(uint32_t rate) override;
     void requestNextVsync() override; // asynchronous
+    void toggleConfigEvents(ISurfaceComposer::ConfigChanged configChangeFlag) override;
 
     // Called in response to requestNextVsync.
     const ResyncCallback resyncCallback;
 
     VSyncRequest vsyncRequest = VSyncRequest::None;
-    const ISurfaceComposer::ConfigChanged configChanged;
+    std::atomic<ISurfaceComposer::ConfigChanged> mConfigChanged =
+            ISurfaceComposer::ConfigChanged::eConfigChangedSuppress;
+    // Store whether we need to force dispatching a config change separately -
+    // if mConfigChanged ever changes before the config change is dispatched
+    // then we still need to propagate an initial config to the app if we
+    // haven't already.
+    std::atomic<bool> mForcedConfigChangeDispatch = false;
 
 private:
     virtual void onFirstRef();
@@ -110,7 +117,8 @@
     virtual void onHotplugReceived(PhysicalDisplayId displayId, bool connected) = 0;
 
     // called when SF changes the active config and apps needs to be notified about the change
-    virtual void onConfigChanged(PhysicalDisplayId displayId, HwcConfigIndexType configId) = 0;
+    virtual void onConfigChanged(PhysicalDisplayId displayId, HwcConfigIndexType configId,
+                                 nsecs_t vsyncPeriod) = 0;
 
     virtual void dump(std::string& result) const = 0;
 
@@ -121,6 +129,11 @@
     virtual void setVsyncRate(uint32_t rate, const sp<EventThreadConnection>& connection) = 0;
     // Requests the next vsync. If resetIdleTimer is set to true, it resets the idle timer.
     virtual void requestNextVsync(const sp<EventThreadConnection>& connection) = 0;
+
+    // Dispatches the most recent configuration
+    // Usage of this method assumes that only the primary internal display
+    // supports multiple display configurations.
+    virtual void requestLatestConfig() = 0;
 };
 
 namespace impl {
@@ -138,6 +151,7 @@
     status_t registerDisplayEventConnection(const sp<EventThreadConnection>& connection) override;
     void setVsyncRate(uint32_t rate, const sp<EventThreadConnection>& connection) override;
     void requestNextVsync(const sp<EventThreadConnection>& connection) override;
+    void requestLatestConfig() override;
 
     // called before the screen is turned off from main thread
     void onScreenReleased() override;
@@ -147,7 +161,8 @@
 
     void onHotplugReceived(PhysicalDisplayId displayId, bool connected) override;
 
-    void onConfigChanged(PhysicalDisplayId displayId, HwcConfigIndexType configId) override;
+    void onConfigChanged(PhysicalDisplayId displayId, HwcConfigIndexType configId,
+                         nsecs_t vsyncPeriod) override;
 
     void dump(std::string& result) const override;
 
@@ -182,6 +197,7 @@
 
     std::vector<wp<EventThreadConnection>> mDisplayEventConnections GUARDED_BY(mMutex);
     std::deque<DisplayEventReceiver::Event> mPendingEvents GUARDED_BY(mMutex);
+    DisplayEventReceiver::Event mLastConfigChangeEvent GUARDED_BY(mMutex);
 
     // VSYNC state of connected display.
     struct VSyncState {
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 71a6a2f..8fe7fcb 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -186,9 +186,9 @@
 }
 
 void Scheduler::onConfigChanged(ConnectionHandle handle, PhysicalDisplayId displayId,
-                                HwcConfigIndexType configId) {
+                                HwcConfigIndexType configId, nsecs_t vsyncPeriod) {
     RETURN_IF_INVALID_HANDLE(handle);
-    mConnections[handle].thread->onConfigChanged(displayId, configId);
+    mConnections[handle].thread->onConfigChanged(displayId, configId, vsyncPeriod);
 }
 
 void Scheduler::dump(ConnectionHandle handle, std::string& result) const {
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 15277ce..d1d5715 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -75,7 +75,8 @@
     sp<EventThreadConnection> getEventConnection(ConnectionHandle);
 
     void onHotplugReceived(ConnectionHandle, PhysicalDisplayId, bool connected);
-    void onConfigChanged(ConnectionHandle, PhysicalDisplayId, HwcConfigIndexType configId);
+    void onConfigChanged(ConnectionHandle, PhysicalDisplayId, HwcConfigIndexType configId,
+                         nsecs_t vsyncPeriod);
 
     void onScreenAcquired(ConnectionHandle);
     void onScreenReleased(ConnectionHandle);
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index fed2395..6e827ac 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -956,8 +956,11 @@
     ATRACE_INT("ActiveConfigFPS", refreshRate.fps);
 
     if (mUpcomingActiveConfig.event != Scheduler::ConfigEvent::None) {
+        const nsecs_t vsyncPeriod =
+                mRefreshRateConfigs->getRefreshRateFromConfigId(mUpcomingActiveConfig.configId)
+                        .vsyncPeriod;
         mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value,
-                                    mUpcomingActiveConfig.configId);
+                                    mUpcomingActiveConfig.configId, vsyncPeriod);
     }
 }
 
@@ -2614,6 +2617,17 @@
     mRegionSamplingThread =
             new RegionSamplingThread(*this, *mScheduler,
                                      RegionSamplingThread::EnvironmentTimingTunables());
+    // Dispatch a config change request for the primary display on scheduler
+    // initialization, so that the EventThreads always contain a reference to a
+    // prior configuration.
+    //
+    // This is a bit hacky, but this avoids a back-pointer into the main SF
+    // classes from EventThread, and there should be no run-time binder cost
+    // anyway since there are no connected apps at this point.
+    const nsecs_t vsyncPeriod =
+            mRefreshRateConfigs->getRefreshRateFromConfigId(currentConfig).vsyncPeriod;
+    mScheduler->onConfigChanged(mAppConnectionHandle, primaryDisplayId.value, currentConfig,
+                                vsyncPeriod);
 }
 
 void SurfaceFlinger::commitTransaction()
@@ -5499,7 +5513,10 @@
 
         auto configId = HwcConfigIndexType(defaultConfig);
         display->setActiveConfig(configId);
-        mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value, configId);
+        const nsecs_t vsyncPeriod =
+                mRefreshRateConfigs->getRefreshRateFromConfigId(configId).vsyncPeriod;
+        mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value, configId,
+                                    vsyncPeriod);
         return NO_ERROR;
     }
 
@@ -5523,8 +5540,10 @@
     // TODO(b/140204874): This hack triggers a notification that something has changed, so
     // that listeners that care about a change in allowed configs can get the notification.
     // Giving current ActiveConfig so that most other listeners would just drop the event
+    const nsecs_t vsyncPeriod =
+            mRefreshRateConfigs->getRefreshRateFromConfigId(display->getActiveConfig()).vsyncPeriod;
     mScheduler->onConfigChanged(mAppConnectionHandle, display->getId()->value,
-                                display->getActiveConfig());
+                                display->getActiveConfig(), vsyncPeriod);
 
     if (mRefreshRateConfigs->refreshRateSwitchingSupported()) {
         auto configId = mScheduler->getPreferredConfigId();
diff --git a/services/surfaceflinger/tests/unittests/EventThreadTest.cpp b/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
index 80bca02..61d4f47 100644
--- a/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
+++ b/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
@@ -85,7 +85,8 @@
     void expectHotplugEventReceivedByConnection(PhysicalDisplayId expectedDisplayId,
                                                 bool expectedConnected);
     void expectConfigChangedEventReceivedByConnection(PhysicalDisplayId expectedDisplayId,
-                                                      int32_t expectedConfigId);
+                                                      int32_t expectedConfigId,
+                                                      nsecs_t expectedVsyncPeriod);
 
     AsyncCallRecorder<void (*)(bool)> mVSyncSetEnabledCallRecorder;
     AsyncCallRecorder<void (*)(VSyncSource::Callback*)> mVSyncSetCallbackCallRecorder;
@@ -209,13 +210,15 @@
 }
 
 void EventThreadTest::expectConfigChangedEventReceivedByConnection(
-        PhysicalDisplayId expectedDisplayId, int32_t expectedConfigId) {
+        PhysicalDisplayId expectedDisplayId, int32_t expectedConfigId,
+        nsecs_t expectedVsyncPeriod) {
     auto args = mConnectionEventCallRecorder.waitForCall();
     ASSERT_TRUE(args.has_value());
     const auto& event = std::get<0>(args.value());
     EXPECT_EQ(DisplayEventReceiver::DISPLAY_EVENT_CONFIG_CHANGED, event.header.type);
     EXPECT_EQ(expectedDisplayId, event.header.displayId);
     EXPECT_EQ(expectedConfigId, event.config.configId);
+    EXPECT_EQ(expectedVsyncPeriod, event.config.vsyncPeriod);
 }
 
 namespace {
@@ -450,18 +453,18 @@
 }
 
 TEST_F(EventThreadTest, postConfigChangedPrimary) {
-    mThread->onConfigChanged(INTERNAL_DISPLAY_ID, HwcConfigIndexType(7));
-    expectConfigChangedEventReceivedByConnection(INTERNAL_DISPLAY_ID, 7);
+    mThread->onConfigChanged(INTERNAL_DISPLAY_ID, HwcConfigIndexType(7), 16666666);
+    expectConfigChangedEventReceivedByConnection(INTERNAL_DISPLAY_ID, 7, 16666666);
 }
 
 TEST_F(EventThreadTest, postConfigChangedExternal) {
-    mThread->onConfigChanged(EXTERNAL_DISPLAY_ID, HwcConfigIndexType(5));
-    expectConfigChangedEventReceivedByConnection(EXTERNAL_DISPLAY_ID, 5);
+    mThread->onConfigChanged(EXTERNAL_DISPLAY_ID, HwcConfigIndexType(5), 16666666);
+    expectConfigChangedEventReceivedByConnection(EXTERNAL_DISPLAY_ID, 5, 16666666);
 }
 
 TEST_F(EventThreadTest, postConfigChangedPrimary64bit) {
-    mThread->onConfigChanged(DISPLAY_ID_64BIT, HwcConfigIndexType(7));
-    expectConfigChangedEventReceivedByConnection(DISPLAY_ID_64BIT, 7);
+    mThread->onConfigChanged(DISPLAY_ID_64BIT, HwcConfigIndexType(7), 16666666);
+    expectConfigChangedEventReceivedByConnection(DISPLAY_ID_64BIT, 7, 16666666);
 }
 
 TEST_F(EventThreadTest, suppressConfigChanged) {
@@ -470,8 +473,8 @@
             createConnection(suppressConnectionEventRecorder,
                              ISurfaceComposer::eConfigChangedSuppress);
 
-    mThread->onConfigChanged(INTERNAL_DISPLAY_ID, HwcConfigIndexType(9));
-    expectConfigChangedEventReceivedByConnection(INTERNAL_DISPLAY_ID, 9);
+    mThread->onConfigChanged(INTERNAL_DISPLAY_ID, HwcConfigIndexType(9), 16666666);
+    expectConfigChangedEventReceivedByConnection(INTERNAL_DISPLAY_ID, 9, 16666666);
 
     auto args = suppressConnectionEventRecorder.waitForCall();
     ASSERT_FALSE(args.has_value());
diff --git a/services/surfaceflinger/tests/unittests/mock/MockEventThread.h b/services/surfaceflinger/tests/unittests/mock/MockEventThread.h
index f7c3804..9bda095 100644
--- a/services/surfaceflinger/tests/unittests/mock/MockEventThread.h
+++ b/services/surfaceflinger/tests/unittests/mock/MockEventThread.h
@@ -33,13 +33,14 @@
     MOCK_METHOD0(onScreenReleased, void());
     MOCK_METHOD0(onScreenAcquired, void());
     MOCK_METHOD2(onHotplugReceived, void(PhysicalDisplayId, bool));
-    MOCK_METHOD2(onConfigChanged, void(PhysicalDisplayId, HwcConfigIndexType));
+    MOCK_METHOD3(onConfigChanged, void(PhysicalDisplayId, HwcConfigIndexType, nsecs_t));
     MOCK_CONST_METHOD1(dump, void(std::string&));
     MOCK_METHOD1(setPhaseOffset, void(nsecs_t phaseOffset));
     MOCK_METHOD1(registerDisplayEventConnection,
                  status_t(const sp<android::EventThreadConnection> &));
     MOCK_METHOD2(setVsyncRate, void(uint32_t, const sp<android::EventThreadConnection> &));
     MOCK_METHOD1(requestNextVsync, void(const sp<android::EventThreadConnection> &));
+    MOCK_METHOD0(requestLatestConfig, void());
     MOCK_METHOD1(pauseVsyncCallback, void(bool));
 };