diff --git a/libs/nativedisplay/AChoreographer.cpp b/libs/nativedisplay/AChoreographer.cpp
index 05ff93e..7e71ede 100644
--- a/libs/nativedisplay/AChoreographer.cpp
+++ b/libs/nativedisplay/AChoreographer.cpp
@@ -17,11 +17,7 @@
 #define LOG_TAG "Choreographer"
 //#define LOG_NDEBUG 0
 
-#include <cinttypes>
-#include <queue>
-#include <thread>
-
-#include <android/choreographer.h>
+#include <apex/choreographer.h>
 #include <gui/DisplayEventDispatcher.h>
 #include <gui/ISurfaceComposer.h>
 #include <gui/SurfaceComposerClient.h>
@@ -29,6 +25,11 @@
 #include <utils/Mutex.h>
 #include <utils/Timers.h>
 
+#include <cinttypes>
+#include <optional>
+#include <queue>
+#include <thread>
+
 namespace android {
 
 static inline const char* toString(bool value) {
@@ -48,11 +49,17 @@
     }
 };
 
+struct RefreshRateCallback {
+    AChoreographer_refreshRateCallback callback;
+    void* data;
+};
 
 class Choreographer : public DisplayEventDispatcher, public MessageHandler {
 public:
     void postFrameCallbackDelayed(AChoreographer_frameCallback cb,
                                   AChoreographer_frameCallback64 cb64, void* data, nsecs_t delay);
+    void registerRefreshRateCallback(AChoreographer_refreshRateCallback cb, void* data);
+    void unregisterRefreshRateCallback(AChoreographer_refreshRateCallback cb);
 
     enum {
         MSG_SCHEDULE_CALLBACKS = 0,
@@ -71,18 +78,23 @@
 
     void dispatchVsync(nsecs_t timestamp, PhysicalDisplayId displayId, uint32_t count) override;
     void dispatchHotplug(nsecs_t timestamp, PhysicalDisplayId displayId, bool connected) override;
-    void dispatchConfigChanged(nsecs_t timestamp, PhysicalDisplayId displayId,
-                               int32_t configId) override;
+    void dispatchConfigChanged(nsecs_t timestamp, PhysicalDisplayId displayId, int32_t configId,
+                               nsecs_t vsyncPeriod) override;
 
     void scheduleCallbacks();
 
     // Protected by mLock
-    std::priority_queue<FrameCallback> mCallbacks;
+    std::priority_queue<FrameCallback> mFrameCallbacks;
+
+    // Protected by mLock
+    std::vector<RefreshRateCallback> mRefreshRateCallbacks;
+    nsecs_t mVsyncPeriod = 0;
 
     mutable Mutex mLock;
 
     const sp<Looper> mLooper;
     const std::thread::id mThreadId;
+    const std::optional<PhysicalDisplayId> mInternalDisplayId;
 };
 
 
@@ -104,9 +116,11 @@
     return gChoreographer;
 }
 
-Choreographer::Choreographer(const sp<Looper>& looper) :
-    DisplayEventDispatcher(looper), mLooper(looper), mThreadId(std::this_thread::get_id()) {
-}
+Choreographer::Choreographer(const sp<Looper>& looper)
+      : DisplayEventDispatcher(looper),
+        mLooper(looper),
+        mThreadId(std::this_thread::get_id()),
+        mInternalDisplayId(SurfaceComposerClient::getInternalDisplayId()) {}
 
 void Choreographer::postFrameCallbackDelayed(
         AChoreographer_frameCallback cb, AChoreographer_frameCallback64 cb64, void* data, nsecs_t delay) {
@@ -114,7 +128,7 @@
     FrameCallback callback{cb, cb64, data, now + delay};
     {
         AutoMutex _l{mLock};
-        mCallbacks.push(callback);
+        mFrameCallbacks.push(callback);
     }
     if (callback.dueTime <= now) {
         if (std::this_thread::get_id() != mThreadId) {
@@ -129,10 +143,31 @@
     }
 }
 
+void Choreographer::registerRefreshRateCallback(AChoreographer_refreshRateCallback cb, void* data) {
+    {
+        AutoMutex _l{mLock};
+        mRefreshRateCallbacks.emplace_back(RefreshRateCallback{cb, data});
+        toggleConfigEvents(ISurfaceComposer::ConfigChanged::eConfigChangedDispatch);
+    }
+}
+
+void Choreographer::unregisterRefreshRateCallback(AChoreographer_refreshRateCallback cb) {
+    {
+        AutoMutex _l{mLock};
+        std::remove_if(mRefreshRateCallbacks.begin(), mRefreshRateCallbacks.end(),
+                       [&](const RefreshRateCallback& callback) {
+                           return cb == callback.callback;
+                       });
+        if (mRefreshRateCallbacks.empty()) {
+            toggleConfigEvents(ISurfaceComposer::ConfigChanged::eConfigChangedSuppress);
+        }
+    }
+}
+
 void Choreographer::scheduleCallbacks() {
     AutoMutex _{mLock};
     nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
-    if (mCallbacks.top().dueTime <= now) {
+    if (mFrameCallbacks.top().dueTime <= now) {
         ALOGV("choreographer %p ~ scheduling vsync", this);
         scheduleVsync();
         return;
@@ -147,9 +182,9 @@
     {
         AutoMutex _l{mLock};
         nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
-        while (!mCallbacks.empty() && mCallbacks.top().dueTime < now) {
-            callbacks.push_back(mCallbacks.top());
-            mCallbacks.pop();
+        while (!mFrameCallbacks.empty() && mFrameCallbacks.top().dueTime < now) {
+            callbacks.push_back(mFrameCallbacks.top());
+            mFrameCallbacks.pop();
         }
     }
     for (const auto& cb : callbacks) {
@@ -167,11 +202,25 @@
             this, displayId, toString(connected));
 }
 
-void Choreographer::dispatchConfigChanged(nsecs_t, PhysicalDisplayId displayId,
-                                          int32_t configId) {
-    ALOGV("choreographer %p ~ received config changed event (displayId=%"
-            ANDROID_PHYSICAL_DISPLAY_ID_FORMAT ", configId=%s), ignoring.",
-            this, displayId, toString(configId));
+// TODO(b/74619554): The PhysicalDisplayId is ignored because currently
+// Choreographer only supports dispatching VSYNC events for the internal
+// display, so as such Choreographer does not support the notion of multiple
+// displays. When multi-display choreographer is properly supported, then
+// PhysicalDisplayId should no longer be ignored.
+void Choreographer::dispatchConfigChanged(nsecs_t, PhysicalDisplayId, int32_t,
+                                          nsecs_t vsyncPeriod) {
+    {
+        AutoMutex _l{mLock};
+        for (const auto& cb : mRefreshRateCallbacks) {
+            // Only perform the callback when the old refresh rate is different
+            // from the new refresh rate, so that we don't dispatch the callback
+            // on every single configuration change.
+            if (mVsyncPeriod != vsyncPeriod) {
+                cb.callback(vsyncPeriod, cb.data);
+                mVsyncPeriod = vsyncPeriod;
+            }
+        }
+    }
 }
 
 void Choreographer::handleMessage(const Message& message) {
@@ -223,3 +272,12 @@
     AChoreographer_to_Choreographer(choreographer)->postFrameCallbackDelayed(
             nullptr, callback, data, ms2ns(delayMillis));
 }
+void AChoreographer_registerRefreshRateCallback(AChoreographer* choreographer,
+                                                AChoreographer_refreshRateCallback callback,
+                                                void* data) {
+    AChoreographer_to_Choreographer(choreographer)->registerRefreshRateCallback(callback, data);
+}
+void AChoreographer_unregisterRefreshRateCallback(AChoreographer* choreographer,
+                                                  AChoreographer_refreshRateCallback callback) {
+    AChoreographer_to_Choreographer(choreographer)->unregisterRefreshRateCallback(callback);
+}
diff --git a/libs/nativedisplay/include/apex/choreographer.h b/libs/nativedisplay/include/apex/choreographer.h
new file mode 100644
index 0000000..352213e
--- /dev/null
+++ b/libs/nativedisplay/include/apex/choreographer.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2019 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.
+ */
+
+#pragma once
+
+#include <android/choreographer.h>
+#include <inttypes.h>
+
+__BEGIN_DECLS
+
+/**
+ * Prototype of the function that is called when the display refresh rate
+ * changes. It's passed the new vsync period in nanoseconds, as well as the data
+ * pointer provided by the application that registered a callback.
+ */
+typedef void (*AChoreographer_refreshRateCallback)(int64_t vsyncPeriodNanos, void* data);
+
+/**
+ * Registers a callback to be run when the display refresh rate changes.
+ */
+void AChoreographer_registerRefreshRateCallback(AChoreographer* choreographer,
+                                                AChoreographer_refreshRateCallback, void* data);
+
+/**
+ * Unregisters a callback to be run when the display refresh rate changes.
+ */
+void AChoreographer_unregisterRefreshRateCallback(AChoreographer* choreographer,
+                                                  AChoreographer_refreshRateCallback);
+
+__END_DECLS
diff --git a/libs/nativedisplay/libnativedisplay.map.txt b/libs/nativedisplay/libnativedisplay.map.txt
index 3b29c18..3b6a241 100644
--- a/libs/nativedisplay/libnativedisplay.map.txt
+++ b/libs/nativedisplay/libnativedisplay.map.txt
@@ -5,6 +5,8 @@
     AChoreographer_postFrameCallbackDelayed; # apex # introduced=30
     AChoreographer_postFrameCallback64; # apex # introduced=30
     AChoreographer_postFrameCallbackDelayed64; # apex # introduced=30
+    AChoreographer_registerRefreshRateCallback; # apex # introduced=30
+    AChoreographer_unregisterRefreshRateCallback; # apex # introduced=30
   local:
     *;
 };