diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 60681a2..26e11e5 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -123,19 +123,22 @@
     promotePacesetterDisplay(pacesetterIdOpt);
 }
 
-void Scheduler::registerDisplay(PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr) {
+void Scheduler::registerDisplay(PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr,
+                                PhysicalDisplayId activeDisplayId) {
     auto schedulePtr =
             std::make_shared<VsyncSchedule>(selectorPtr->getActiveMode().modePtr, mFeatures,
                                             [this](PhysicalDisplayId id, bool enable) {
                                                 onHardwareVsyncRequest(id, enable);
                                             });
 
-    registerDisplayInternal(displayId, std::move(selectorPtr), std::move(schedulePtr));
+    registerDisplayInternal(displayId, std::move(selectorPtr), std::move(schedulePtr),
+                            activeDisplayId);
 }
 
 void Scheduler::registerDisplayInternal(PhysicalDisplayId displayId,
                                         RefreshRateSelectorPtr selectorPtr,
-                                        VsyncSchedulePtr schedulePtr) {
+                                        VsyncSchedulePtr schedulePtr,
+                                        PhysicalDisplayId activeDisplayId) {
     demotePacesetterDisplay();
 
     auto [pacesetterVsyncSchedule, isNew] = [&]() FTL_FAKE_GUARD(kMainThreadContext) {
@@ -145,7 +148,7 @@
                                                        std::move(schedulePtr), mFeatures)
                                    .second;
 
-        return std::make_pair(promotePacesetterDisplayLocked(), isNew);
+        return std::make_pair(promotePacesetterDisplayLocked(activeDisplayId), isNew);
     }();
 
     applyNewVsyncSchedule(std::move(pacesetterVsyncSchedule));
@@ -158,7 +161,9 @@
     dispatchHotplug(displayId, Hotplug::Connected);
 }
 
-void Scheduler::unregisterDisplay(PhysicalDisplayId displayId) {
+void Scheduler::unregisterDisplay(PhysicalDisplayId displayId, PhysicalDisplayId activeDisplayId) {
+    LOG_ALWAYS_FATAL_IF(displayId == activeDisplayId, "Cannot unregister the active display!");
+
     dispatchHotplug(displayId, Hotplug::Disconnected);
 
     demotePacesetterDisplay();
@@ -173,7 +178,7 @@
         // headless virtual display.)
         LOG_ALWAYS_FATAL_IF(mDisplays.empty(), "Cannot unregister all displays!");
 
-        pacesetterVsyncSchedule = promotePacesetterDisplayLocked();
+        pacesetterVsyncSchedule = promotePacesetterDisplayLocked(activeDisplayId);
     }
     applyNewVsyncSchedule(std::move(pacesetterVsyncSchedule));
 }
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index ccaa05f..1a4aa79 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -101,9 +101,16 @@
     using ConstVsyncSchedulePtr = std::shared_ptr<const VsyncSchedule>;
     using VsyncSchedulePtr = std::shared_ptr<VsyncSchedule>;
 
-    void registerDisplay(PhysicalDisplayId, RefreshRateSelectorPtr) REQUIRES(kMainThreadContext)
+    // After registration/unregistration, `activeDisplayId` is promoted to pacesetter. Note that the
+    // active display is never unregistered, since hotplug disconnect never happens for activatable
+    // displays, i.e. a foldable's internal displays or otherwise the (internal or external) primary
+    // display.
+    // TODO: b/255635821 - Remove active display parameters.
+    void registerDisplay(PhysicalDisplayId, RefreshRateSelectorPtr,
+                         PhysicalDisplayId activeDisplayId) REQUIRES(kMainThreadContext)
             EXCLUDES(mDisplayLock);
-    void unregisterDisplay(PhysicalDisplayId) REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock);
+    void unregisterDisplay(PhysicalDisplayId, PhysicalDisplayId activeDisplayId)
+            REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock);
 
     void run();
 
@@ -390,8 +397,9 @@
     // the caller on the main thread to avoid deadlock, since the timer thread locks it before exit.
     void demotePacesetterDisplay() REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock, mPolicyLock);
 
-    void registerDisplayInternal(PhysicalDisplayId, RefreshRateSelectorPtr, VsyncSchedulePtr)
-            REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock);
+    void registerDisplayInternal(PhysicalDisplayId, RefreshRateSelectorPtr, VsyncSchedulePtr,
+                                 PhysicalDisplayId activeDisplayId) REQUIRES(kMainThreadContext)
+            EXCLUDES(mDisplayLock);
 
     struct Policy;
 
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 596ec12..5fa6d26 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3855,7 +3855,8 @@
         ftl::FakeGuard guard(kMainThreadContext);
 
         // For hotplug reconnect, renew the registration since display modes have been reloaded.
-        mScheduler->registerDisplay(display->getPhysicalId(), display->holdRefreshRateSelector());
+        mScheduler->registerDisplay(display->getPhysicalId(), display->holdRefreshRateSelector(),
+                                    mActiveDisplayId);
     }
 
     if (display->isVirtual()) {
@@ -3894,7 +3895,7 @@
         if (display->isVirtual()) {
             releaseVirtualDisplay(display->getVirtualId());
         } else {
-            mScheduler->unregisterDisplay(display->getPhysicalId());
+            mScheduler->unregisterDisplay(display->getPhysicalId(), mActiveDisplayId);
         }
     }
 
@@ -4506,7 +4507,8 @@
                                              getFactory(), activeRefreshRate, *mTimeStats);
 
     // The pacesetter must be registered before EventThread creation below.
-    mScheduler->registerDisplay(display->getPhysicalId(), display->holdRefreshRateSelector());
+    mScheduler->registerDisplay(display->getPhysicalId(), display->holdRefreshRateSelector(),
+                                mActiveDisplayId);
     if (FlagManager::getInstance().vrr_config()) {
         mScheduler->setRenderRate(display->getPhysicalId(), activeMode.fps,
                                   /*applyImmediately*/ true);
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index 4fb0690..fc54a8b 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -343,12 +343,15 @@
 }
 
 TEST_F(SchedulerTest, chooseDisplayModesMultipleDisplays) {
+    constexpr PhysicalDisplayId kActiveDisplayId = kDisplayId1;
     mScheduler->registerDisplay(kDisplayId1,
                                 std::make_shared<RefreshRateSelector>(kDisplay1Modes,
-                                                                      kDisplay1Mode60->getId()));
+                                                                      kDisplay1Mode60->getId()),
+                                kActiveDisplayId);
     mScheduler->registerDisplay(kDisplayId2,
                                 std::make_shared<RefreshRateSelector>(kDisplay2Modes,
-                                                                      kDisplay2Mode60->getId()));
+                                                                      kDisplay2Mode60->getId()),
+                                kActiveDisplayId);
 
     mScheduler->setDisplayPowerMode(kDisplayId1, hal::PowerMode::ON);
     mScheduler->setDisplayPowerMode(kDisplayId2, hal::PowerMode::ON);
@@ -411,10 +414,10 @@
     {
         // The kDisplayId3 does not support 120Hz, The pacesetter display rate is chosen to be 120
         // Hz. In this case only the display kDisplayId3 choose 60Hz as it does not support 120Hz.
-        mScheduler
-                ->registerDisplay(kDisplayId3,
-                                  std::make_shared<RefreshRateSelector>(kDisplay3Modes,
-                                                                        kDisplay3Mode60->getId()));
+        mScheduler->registerDisplay(kDisplayId3,
+                                    std::make_shared<RefreshRateSelector>(kDisplay3Modes,
+                                                                          kDisplay3Mode60->getId()),
+                                    kActiveDisplayId);
         mScheduler->setDisplayPowerMode(kDisplayId3, hal::PowerMode::ON);
 
         const GlobalSignals globalSignals = {.touch = true};
@@ -457,12 +460,15 @@
 }
 
 TEST_F(SchedulerTest, onFrameSignalMultipleDisplays) {
+    constexpr PhysicalDisplayId kActiveDisplayId = kDisplayId1;
     mScheduler->registerDisplay(kDisplayId1,
                                 std::make_shared<RefreshRateSelector>(kDisplay1Modes,
-                                                                      kDisplay1Mode60->getId()));
+                                                                      kDisplay1Mode60->getId()),
+                                kActiveDisplayId);
     mScheduler->registerDisplay(kDisplayId2,
                                 std::make_shared<RefreshRateSelector>(kDisplay2Modes,
-                                                                      kDisplay2Mode60->getId()));
+                                                                      kDisplay2Mode60->getId()),
+                                kActiveDisplayId);
 
     using VsyncIds = std::vector<std::pair<PhysicalDisplayId, VsyncId>>;
 
@@ -585,7 +591,8 @@
                                 mFlinger.getTimeStats(),
                                 mSchedulerCallback};
 
-    scheduler.registerDisplay(kMode->getPhysicalDisplayId(), vrrSelectorPtr, vrrTracker);
+    scheduler.registerDisplay(kMode->getPhysicalDisplayId(), vrrSelectorPtr, std::nullopt,
+                              vrrTracker);
     vrrSelectorPtr->setActiveMode(kMode->getId(), frameRate);
     scheduler.setRenderRate(kMode->getPhysicalDisplayId(), frameRate, /*applyImmediately*/ false);
     vrrTracker->addVsyncTimestamp(0);
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 198a5de..f063809 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -53,7 +53,7 @@
                       factory, selectorPtr->getActiveMode().fps, timeStats) {
         const auto displayId = selectorPtr->getActiveMode().modePtr->getPhysicalDisplayId();
         registerDisplay(displayId, std::move(selectorPtr), std::move(controller),
-                        std::move(tracker));
+                        std::move(tracker), displayId);
 
         ON_CALL(*this, postMessage).WillByDefault([](sp<MessageHandler>&& handler) {
             // Execute task to prevent broken promise exception on destruction.
@@ -85,14 +85,16 @@
 
     void registerDisplay(
             PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr,
+            std::optional<PhysicalDisplayId> activeDisplayIdOpt = {},
             std::shared_ptr<VSyncTracker> vsyncTracker = std::make_shared<mock::VSyncTracker>()) {
         registerDisplay(displayId, std::move(selectorPtr),
-                        std::make_unique<mock::VsyncController>(), vsyncTracker);
+                        std::make_unique<mock::VsyncController>(), vsyncTracker,
+                        activeDisplayIdOpt.value_or(displayId));
     }
 
     void registerDisplay(PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr,
                          std::unique_ptr<VsyncController> controller,
-                         std::shared_ptr<VSyncTracker> tracker) {
+                         std::shared_ptr<VSyncTracker> tracker, PhysicalDisplayId activeDisplayId) {
         ftl::FakeGuard guard(kMainThreadContext);
         Scheduler::registerDisplayInternal(displayId, std::move(selectorPtr),
                                            std::shared_ptr<VsyncSchedule>(
@@ -101,16 +103,12 @@
                                                                              mock::VSyncDispatch>(),
                                                                      std::move(controller),
                                                                      mockRequestHardwareVsync
-                                                                             .AsStdFunction())));
+                                                                             .AsStdFunction())),
+                                           activeDisplayId);
     }
 
     testing::MockFunction<void(PhysicalDisplayId, bool)> mockRequestHardwareVsync;
 
-    void unregisterDisplay(PhysicalDisplayId displayId) {
-        ftl::FakeGuard guard(kMainThreadContext);
-        Scheduler::unregisterDisplay(displayId);
-    }
-
     void setDisplayPowerMode(PhysicalDisplayId displayId, hal::PowerMode powerMode) {
         ftl::FakeGuard guard(kMainThreadContext);
         Scheduler::setDisplayPowerMode(displayId, powerMode);
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 007383b..4197cbd 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -1118,8 +1118,8 @@
                 if (mFlinger.scheduler() && mSchedulerRegistration) {
                     mFlinger.scheduler()->registerDisplay(*physicalId,
                                                           mCreationArgs.refreshRateSelector,
-                                                          std::move(controller),
-                                                          std::move(tracker));
+                                                          std::move(controller), std::move(tracker),
+                                                          mFlinger.mutableActiveDisplayId());
                 }
             }