diff --git a/services/surfaceflinger/Scheduler/DispSync.cpp b/services/surfaceflinger/Scheduler/DispSync.cpp
index cd6fa41..95ff9d0 100644
--- a/services/surfaceflinger/Scheduler/DispSync.cpp
+++ b/services/surfaceflinger/Scheduler/DispSync.cpp
@@ -79,11 +79,7 @@
         Mutex::Autolock lock(mMutex);
 
         mPhase = phase;
-        if (mReferenceTime != referenceTime) {
-            for (auto& eventListener : mEventListeners) {
-                eventListener.mHasFired = false;
-            }
-        }
+        const bool referenceTimeChanged = mReferenceTime != referenceTime;
         mReferenceTime = referenceTime;
         if (mPeriod != 0 && mPeriod != period && mReferenceTime != 0) {
             // Inflate the reference time to be the most recent predicted
@@ -94,6 +90,13 @@
             mReferenceTime = mReferenceTime + (numOldPeriods)*mPeriod;
         }
         mPeriod = period;
+        if (!mModelLocked && referenceTimeChanged) {
+            for (auto& eventListener : mEventListeners) {
+                eventListener.mHasFired = false;
+                eventListener.mLastEventTime =
+                        mReferenceTime - mPeriod + mPhase + eventListener.mPhase;
+            }
+        }
         if (mTraceDetailedInfo) {
             ATRACE_INT64("DispSync:Period", mPeriod);
             ATRACE_INT64("DispSync:Phase", mPhase + mPeriod / 2);
@@ -115,11 +118,20 @@
     void lockModel() {
         Mutex::Autolock lock(mMutex);
         mModelLocked = true;
+        ATRACE_INT("DispSync:ModelLocked", mModelLocked);
     }
 
     void unlockModel() {
         Mutex::Autolock lock(mMutex);
+        if (mModelLocked) {
+            for (auto& eventListener : mEventListeners) {
+                if (eventListener.mLastEventTime > mReferenceTime) {
+                    eventListener.mHasFired = true;
+                }
+            }
+        }
         mModelLocked = false;
+        ATRACE_INT("DispSync:ModelLocked", mModelLocked);
     }
 
     virtual bool threadLoop() {
@@ -247,6 +259,10 @@
             listener.mLastCallbackTime = lastCallbackTime;
         }
 
+        if (!mModelLocked && listener.mLastEventTime > mReferenceTime) {
+            listener.mHasFired = true;
+        }
+
         mEventListeners.push_back(listener);
 
         mCond.signal();
@@ -493,7 +509,6 @@
         ALOGE("Couldn't set SCHED_FIFO for DispSyncThread");
     }
 
-    reset();
     beginResync();
 
     if (mTraceDetailedInfo && kEnableZeroPhaseTracer) {
@@ -545,17 +560,15 @@
 void DispSync::beginResync() {
     Mutex::Autolock lock(mMutex);
     ALOGV("[%s] beginResync", mName);
-    mThread->unlockModel();
-    mModelUpdated = false;
-    mNumResyncSamples = 0;
+    resetLocked();
 }
 
-bool DispSync::addResyncSample(nsecs_t timestamp, bool* periodChanged) {
+bool DispSync::addResyncSample(nsecs_t timestamp, bool* periodFlushed) {
     Mutex::Autolock lock(mMutex);
 
     ALOGV("[%s] addResyncSample(%" PRId64 ")", mName, ns2us(timestamp));
 
-    *periodChanged = false;
+    *periodFlushed = false;
     const size_t idx = (mFirstResyncSample + mNumResyncSamples) % MAX_RESYNC_SAMPLES;
     mResyncSamples[idx] = timestamp;
     if (mNumResyncSamples == 0) {
@@ -569,16 +582,20 @@
         const nsecs_t lastTimestamp = mResyncSamples[priorIdx];
 
         const nsecs_t observedVsync = std::abs(timestamp - lastTimestamp);
-        if (std::abs(observedVsync - mPendingPeriod) < std::abs(observedVsync - mPeriod)) {
-            // Observed vsync is closer to the pending period, so reset the
-            // model and flush the pending period.
+        if (std::abs(observedVsync - mPendingPeriod) <= std::abs(observedVsync - mIntendedPeriod)) {
+            // Either the observed vsync is closer to the pending period, (and
+            // thus we detected a period change), or the period change will
+            // no-op. In either case, reset the model and flush the pending
+            // period.
             resetLocked();
+            mIntendedPeriod = mPendingPeriod;
             mPeriod = mPendingPeriod;
             mPendingPeriod = 0;
             if (mTraceDetailedInfo) {
                 ATRACE_INT("DispSync:PendingPeriod", mPendingPeriod);
+                ATRACE_INT("DispSync:IntendedPeriod", mIntendedPeriod);
             }
-            *periodChanged = true;
+            *periodFlushed = true;
         }
     }
     // Always update the reference time with the most recent timestamp.
@@ -609,6 +626,7 @@
     bool modelLocked = mModelUpdated && mError < (kErrorThreshold / 2) && mPendingPeriod == 0;
     ALOGV("[%s] addResyncSample returning %s", mName, modelLocked ? "locked" : "unlocked");
     if (modelLocked) {
+        *periodFlushed = true;
         mThread->lockModel();
     }
     return !modelLocked;
@@ -643,10 +661,17 @@
 
 void DispSync::setPeriod(nsecs_t period) {
     Mutex::Autolock lock(mMutex);
-    if (mTraceDetailedInfo) {
-        ATRACE_INT("DispSync:PendingPeriod", period);
+
+    const bool pendingPeriodShouldChange =
+            period != mIntendedPeriod || (period == mIntendedPeriod && mPendingPeriod != 0);
+
+    if (pendingPeriodShouldChange) {
+        mPendingPeriod = period;
     }
-    mPendingPeriod = period;
+    if (mTraceDetailedInfo) {
+        ATRACE_INT("DispSync:IntendedPeriod", mIntendedPeriod);
+        ATRACE_INT("DispSync:PendingPeriod", mPendingPeriod);
+    }
 }
 
 nsecs_t DispSync::getPeriod() {
@@ -764,6 +789,9 @@
     mPresentSampleOffset = 0;
     mError = 0;
     mZeroErrSamplesCount = 0;
+    if (mTraceDetailedInfo) {
+        ATRACE_INT64("DispSync:Error", mError);
+    }
     for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
         mPresentFences[i] = FenceTime::NO_FENCE;
     }
diff --git a/services/surfaceflinger/Scheduler/DispSync.h b/services/surfaceflinger/Scheduler/DispSync.h
index 8f8b8e7..3e33c7e 100644
--- a/services/surfaceflinger/Scheduler/DispSync.h
+++ b/services/surfaceflinger/Scheduler/DispSync.h
@@ -49,7 +49,7 @@
     virtual void reset() = 0;
     virtual bool addPresentFence(const std::shared_ptr<FenceTime>&) = 0;
     virtual void beginResync() = 0;
-    virtual bool addResyncSample(nsecs_t timestamp, bool* periodChanged) = 0;
+    virtual bool addResyncSample(nsecs_t timestamp, bool* periodFlushed) = 0;
     virtual void endResync() = 0;
     virtual void setPeriod(nsecs_t period) = 0;
     virtual nsecs_t getPeriod() = 0;
@@ -120,17 +120,19 @@
     // from the hardware vsync events.
     void beginResync() override;
     // Adds a vsync sample to the dispsync model. The timestamp is the time
-    // of the vsync event that fired. periodChanged will return true if the
+    // of the vsync event that fired. periodFlushed will return true if the
     // vsync period was detected to have changed to mPendingPeriod.
     //
     // This method will return true if more vsync samples are needed to lock
     // down the DispSync model, and false otherwise.
-    bool addResyncSample(nsecs_t timestamp, bool* periodChanged) override;
+    // periodFlushed will be set to true if mPendingPeriod is flushed to
+    // mIntendedPeriod, and false otherwise.
+    bool addResyncSample(nsecs_t timestamp, bool* periodFlushed) override;
     void endResync() override;
 
     // The setPeriod method sets the vsync event model's period to a specific
-    // value.  This should be used to prime the model when a display is first
-    // turned on.  It should NOT be used after that.
+    // value. This should be used to prime the model when a display is first
+    // turned on, or when a refresh rate change is requested.
     void setPeriod(nsecs_t period) override;
 
     // The getPeriod method returns the current vsync period.
@@ -205,6 +207,11 @@
     // nanoseconds.
     nsecs_t mPeriod;
 
+    // mIntendedPeriod is the intended period of the modeled vsync events in
+    // nanoseconds. Under ideal conditions this should be similar if not the
+    // same as mPeriod, plus or minus an observed error.
+    nsecs_t mIntendedPeriod = 0;
+
     // mPendingPeriod is the proposed period change in nanoseconds.
     // If mPendingPeriod differs from mPeriod and is nonzero, it will
     // be flushed to mPeriod when we detect that the hardware switched
@@ -236,8 +243,8 @@
     // process to store information about the hardware vsync event times used
     // to compute the model.
     nsecs_t mResyncSamples[MAX_RESYNC_SAMPLES] = {0};
-    size_t mFirstResyncSample;
-    size_t mNumResyncSamples;
+    size_t mFirstResyncSample = 0;
+    size_t mNumResyncSamples = 0;
     int mNumResyncSamplesSincePresent;
 
     // These member variables store information about the present fences used
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 513436a..e2a348e 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -280,13 +280,13 @@
     }
 }
 
-void Scheduler::addResyncSample(const nsecs_t timestamp, bool* periodChanged) {
+void Scheduler::addResyncSample(const nsecs_t timestamp, bool* periodFlushed) {
     bool needsHwVsync = false;
-    *periodChanged = false;
+    *periodFlushed = false;
     { // Scope for the lock
         std::lock_guard<std::mutex> lock(mHWVsyncLock);
         if (mPrimaryHWVsyncEnabled) {
-            needsHwVsync = mPrimaryDispSync->addResyncSample(timestamp, periodChanged);
+            needsHwVsync = mPrimaryDispSync->addResyncSample(timestamp, periodFlushed);
         }
     }
 
@@ -415,7 +415,7 @@
     ATRACE_INT("ExpiredKernelIdleTimer", 0);
     std::lock_guard<std::mutex> lock(mCallbackLock);
     if (mGetVsyncPeriod) {
-        resyncToHardwareVsync(false, mGetVsyncPeriod());
+        resyncToHardwareVsync(true, mGetVsyncPeriod());
     }
 }
 
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 96d4bd5..d311f62 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -135,13 +135,18 @@
 
     void enableHardwareVsync();
     void disableHardwareVsync(bool makeUnavailable);
+    // Resyncs the scheduler to hardware vsync.
+    // If makeAvailable is true, then hardware vsync will be turned on.
+    // Otherwise, if hardware vsync is not already enabled then this method will
+    // no-op.
+    // The period is the vsync period from the current display configuration.
     void resyncToHardwareVsync(bool makeAvailable, nsecs_t period);
     // Creates a callback for resyncing.
     ResyncCallback makeResyncCallback(GetVsyncPeriod&& getVsyncPeriod);
     void setRefreshSkipCount(int count);
-    // Passes a vsync sample to DispSync. periodChange will be true if DipSync
-    // detected that the vsync period changed, and false otherwise.
-    void addResyncSample(const nsecs_t timestamp, bool* periodChanged);
+    // Passes a vsync sample to DispSync. periodFlushed will be true if
+    // DispSync detected that the vsync period changed, and false otherwise.
+    void addResyncSample(const nsecs_t timestamp, bool* periodFlushed);
     void addPresentFence(const std::shared_ptr<FenceTime>& fenceTime);
     void setIgnorePresentFences(bool ignore);
     nsecs_t expectedPresentTime();
@@ -292,7 +297,7 @@
     const scheduler::RefreshRateConfigs& mRefreshRateConfigs;
 
     // Global config to force HDR content to work on DEFAULT refreshRate
-    static constexpr bool mForceHDRContentToDefaultRefreshRate = true;
+    static constexpr bool mForceHDRContentToDefaultRefreshRate = false;
 };
 
 } // namespace android
diff --git a/services/surfaceflinger/Scheduler/VSyncModulator.h b/services/surfaceflinger/Scheduler/VSyncModulator.h
index 81a7864..41c3a3a 100644
--- a/services/surfaceflinger/Scheduler/VSyncModulator.h
+++ b/services/surfaceflinger/Scheduler/VSyncModulator.h
@@ -35,6 +35,11 @@
     // sending new transactions.
     const int MIN_EARLY_FRAME_COUNT_TRANSACTION = 2;
 
+    // Number of frames we'll keep the early gl phase offsets once they are activated.
+    // This acts as a low-pass filter to avoid scenarios where we rapidly
+    // switch in and out of gl composition.
+    const int MIN_EARLY_GL_FRAME_COUNT_TRANSACTION = 2;
+
 public:
     struct Offsets {
         nsecs_t sf;
@@ -116,7 +121,7 @@
 
     // Called when we detect from vsync signals that the refresh rate changed.
     // This way we can move out of early offsets if no longer necessary.
-    void onRefreshRateChangeDetected() {
+    void onRefreshRateChangeCompleted() {
         if (!mRefreshRateChangePending) {
             return;
         }
@@ -130,10 +135,14 @@
             mRemainingEarlyFrameCount--;
             updateOffsetsNeeded = true;
         }
-        if (usedRenderEngine != mLastFrameUsedRenderEngine) {
-            mLastFrameUsedRenderEngine = usedRenderEngine;
+        if (usedRenderEngine) {
+            mRemainingRenderEngineUsageCount = MIN_EARLY_GL_FRAME_COUNT_TRANSACTION;
+            updateOffsetsNeeded = true;
+        } else if (mRemainingRenderEngineUsageCount > 0) {
+            mRemainingRenderEngineUsageCount--;
             updateOffsetsNeeded = true;
         }
+
         if (updateOffsetsNeeded) {
             updateOffsets();
         }
@@ -145,7 +154,7 @@
         if (mTransactionStart == Scheduler::TransactionStart::EARLY ||
             mRemainingEarlyFrameCount > 0 || mRefreshRateChangePending) {
             return mEarlyOffsets;
-        } else if (mLastFrameUsedRenderEngine) {
+        } else if (mRemainingRenderEngineUsageCount > 0) {
             return mEarlyGlOffsets;
         } else {
             return mLateOffsets;
@@ -195,9 +204,9 @@
 
     std::atomic<Scheduler::TransactionStart> mTransactionStart =
             Scheduler::TransactionStart::NORMAL;
-    std::atomic<bool> mLastFrameUsedRenderEngine = false;
     std::atomic<bool> mRefreshRateChangePending = false;
     std::atomic<int> mRemainingEarlyFrameCount = 0;
+    std::atomic<int> mRemainingRenderEngineUsageCount = 0;
 };
 
 } // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index dd75868..87c1bf9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -935,9 +935,11 @@
         // Start receiving vsync samples now, so that we can detect a period
         // switch.
         mScheduler->resyncToHardwareVsync(true, getVsyncPeriod());
+        // As we called to set period, we will call to onRefreshRateChangeCompleted once
+        // DispSync model is locked.
+        mVsyncModulator.onRefreshRateChangeInitiated();
         mPhaseOffsets->setRefreshRateType(info.type);
         const auto [early, gl, late] = mPhaseOffsets->getCurrentOffsets();
-        mVsyncModulator.onRefreshRateChangeInitiated();
         mVsyncModulator.setPhaseOffsets(early, gl, late);
     }
     mDesiredActiveConfigChanged = true;
@@ -970,7 +972,6 @@
 
     display->setActiveConfig(mUpcomingActiveConfig.configId);
 
-    mScheduler->resyncToHardwareVsync(true, getVsyncPeriod());
     mPhaseOffsets->setRefreshRateType(mUpcomingActiveConfig.type);
     const auto [early, gl, late] = mPhaseOffsets->getCurrentOffsets();
     mVsyncModulator.setPhaseOffsets(early, gl, late);
@@ -982,6 +983,18 @@
     }
 }
 
+void SurfaceFlinger::desiredActiveConfigChangeDone() {
+    std::lock_guard<std::mutex> lock(mActiveConfigLock);
+    mDesiredActiveConfig.event = Scheduler::ConfigEvent::None;
+    mDesiredActiveConfigChanged = false;
+    ATRACE_INT("DesiredActiveConfigChanged", mDesiredActiveConfigChanged);
+
+    mScheduler->resyncToHardwareVsync(true, getVsyncPeriod());
+    mPhaseOffsets->setRefreshRateType(mUpcomingActiveConfig.type);
+    const auto [early, gl, late] = mPhaseOffsets->getCurrentOffsets();
+    mVsyncModulator.setPhaseOffsets(early, gl, late);
+}
+
 bool SurfaceFlinger::performSetActiveConfig() {
     ATRACE_CALL();
     if (mCheckPendingFence) {
@@ -1011,10 +1024,7 @@
     if (!display || display->getActiveConfig() == desiredActiveConfig.configId) {
         // display is not valid or we are already in the requested mode
         // on both cases there is nothing left to do
-        std::lock_guard<std::mutex> lock(mActiveConfigLock);
-        mDesiredActiveConfig.event = Scheduler::ConfigEvent::None;
-        mDesiredActiveConfigChanged = false;
-        ATRACE_INT("DesiredActiveConfigChanged", mDesiredActiveConfigChanged);
+        desiredActiveConfigChangeDone();
         return false;
     }
 
@@ -1022,11 +1032,7 @@
     // allowed configs might have change by the time we process the refresh.
     // Make sure the desired config is still allowed
     if (!isDisplayConfigAllowed(desiredActiveConfig.configId)) {
-        std::lock_guard<std::mutex> lock(mActiveConfigLock);
-        mDesiredActiveConfig.event = Scheduler::ConfigEvent::None;
-        mDesiredActiveConfig.configId = display->getActiveConfig();
-        mDesiredActiveConfigChanged = false;
-        ATRACE_INT("DesiredActiveConfigChanged", mDesiredActiveConfigChanged);
+        desiredActiveConfigChangeDone();
         return false;
     }
     mUpcomingActiveConfig = desiredActiveConfig;
@@ -1448,10 +1454,10 @@
         return;
     }
 
-    bool periodChanged = false;
-    mScheduler->addResyncSample(timestamp, &periodChanged);
-    if (periodChanged) {
-        mVsyncModulator.onRefreshRateChangeDetected();
+    bool periodFlushed = false;
+    mScheduler->addResyncSample(timestamp, &periodFlushed);
+    if (periodFlushed) {
+        mVsyncModulator.onRefreshRateChangeCompleted();
     }
 }
 
@@ -1524,10 +1530,25 @@
 
 void SurfaceFlinger::setPrimaryVsyncEnabled(bool enabled) {
     ATRACE_CALL();
-    Mutex::Autolock lock(mStateLock);
+
+    // Enable / Disable HWVsync from the main thread to avoid race conditions with
+    // display power state.
+    postMessageAsync(new LambdaMessage(
+            [=]() NO_THREAD_SAFETY_ANALYSIS { setPrimaryVsyncEnabledInternal(enabled); }));
+}
+
+void SurfaceFlinger::setPrimaryVsyncEnabledInternal(bool enabled) {
+    ATRACE_CALL();
+
     if (const auto displayId = getInternalDisplayIdLocked()) {
-        getHwComposer().setVsyncEnabled(*displayId,
-                                        enabled ? HWC2::Vsync::Enable : HWC2::Vsync::Disable);
+        sp<DisplayDevice> display = getDefaultDisplayDeviceLocked();
+        if (display && display->isPoweredOn()) {
+            getHwComposer().setVsyncEnabled(*displayId,
+                                            enabled ? HWC2::Vsync::Enable : HWC2::Vsync::Disable);
+        } else {
+            // Cache the latest vsync state and apply it when screen is on again
+            mEnableHWVsyncScreenOn = enabled;
+        }
     }
 }
 
@@ -4425,6 +4446,11 @@
         // Turn on the display
         getHwComposer().setPowerMode(*displayId, mode);
         if (display->isPrimary() && mode != HWC_POWER_MODE_DOZE_SUSPEND) {
+            if (mEnableHWVsyncScreenOn) {
+                setPrimaryVsyncEnabledInternal(mEnableHWVsyncScreenOn);
+                mEnableHWVsyncScreenOn = false;
+            }
+
             mScheduler->onScreenAcquired(mAppConnectionHandle);
             mScheduler->resyncToHardwareVsync(true, getVsyncPeriod());
         }
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index ddfe88c..46fc4d2 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -293,6 +293,9 @@
     // TODO: this should be made accessible only to EventThread
     void setPrimaryVsyncEnabled(bool enabled);
 
+    // main thread function to enable/disable h/w composer event
+    void setPrimaryVsyncEnabledInternal(bool enabled);
+
     // called on the main thread by MessageQueue when an internal message
     // is received
     // TODO: this should be made accessible only to MessageQueue
@@ -508,13 +511,15 @@
     // Sets the desired active config bit. It obtains the lock, and sets mDesiredActiveConfig.
     void setDesiredActiveConfig(const ActiveConfigInfo& info) REQUIRES(mStateLock);
     // Once HWC has returned the present fence, this sets the active config and a new refresh
-    // rate in SF. It also triggers HWC vsync.
+    // rate in SF.
     void setActiveConfigInternal() REQUIRES(mStateLock);
     // Active config is updated on INVALIDATE call in a state machine-like manner. When the
     // desired config was set, HWC needs to update the panel on the next refresh, and when
     // we receive the fence back, we know that the process was complete. It returns whether
     // we need to wait for the next invalidate
     bool performSetActiveConfig() REQUIRES(mStateLock);
+    // Called when active config is no longer is progress
+    void desiredActiveConfigChangeDone() REQUIRES(mStateLock);
     // called on the main thread in response to setPowerMode()
     void setPowerModeInternal(const sp<DisplayDevice>& display, int mode) REQUIRES(mStateLock);
 
@@ -1166,6 +1171,9 @@
     // The Layer pointer is removed from the set when the destructor is called so there shouldn't
     // be any issues with a raw pointer referencing an invalid object.
     std::unordered_set<Layer*> mOffscreenLayers;
+
+    // Flag to indicate whether to re-enable HWVsync when screen is on
+    bool mEnableHWVsyncScreenOn = false;
 };
 
 } // namespace android
diff --git a/services/surfaceflinger/tests/unittests/mock/MockDispSync.h b/services/surfaceflinger/tests/unittests/mock/MockDispSync.h
index 12a349d..9ca116d 100644
--- a/services/surfaceflinger/tests/unittests/mock/MockDispSync.h
+++ b/services/surfaceflinger/tests/unittests/mock/MockDispSync.h
@@ -35,6 +35,7 @@
     MOCK_METHOD0(endResync, void());
     MOCK_METHOD1(setPeriod, void(nsecs_t));
     MOCK_METHOD0(getPeriod, nsecs_t());
+    MOCK_METHOD0(getIntendedPeriod, nsecs_t());
     MOCK_METHOD1(setRefreshSkipCount, void(int));
     MOCK_CONST_METHOD1(computeNextRefresh, nsecs_t(int));
     MOCK_METHOD1(setIgnorePresentFences, void(bool));