diff --git a/services/surfaceflinger/Scheduler/VSyncReactor.cpp b/services/surfaceflinger/Scheduler/VSyncReactor.cpp
index 186a2d6..9b8f310 100644
--- a/services/surfaceflinger/Scheduler/VSyncReactor.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncReactor.cpp
@@ -217,6 +217,11 @@
         mMoreSamplesNeeded = mTracker.needsMoreSamples();
     }
 
+    if (mExternalIgnoreFences) {
+      // keep HWVSync on as long as we ignore present fences.
+      mMoreSamplesNeeded = true;
+    }
+
     if (!mMoreSamplesNeeded) {
         setIgnorePresentFencesInternal(false);
     }
diff --git a/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp b/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp
index 8d9623d..e3aa4ef 100644
--- a/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp
+++ b/services/surfaceflinger/tests/unittests/VSyncReactorTest.cpp
@@ -195,9 +195,7 @@
 
 TEST_F(VSyncReactorTest, ignoresProperlyAfterAPeriodConfirmation) {
     bool periodFlushed = true;
-    EXPECT_CALL(*mMockTracker, addVsyncTimestamp(_)).Times(2);
-    mReactor.setIgnorePresentFences(true);
-
+    EXPECT_CALL(*mMockTracker, addVsyncTimestamp(_)).Times(3);
     nsecs_t const newPeriod = 5000;
 
     mReactor.onDisplayModeChanged(displayMode(newPeriod), false);
@@ -207,7 +205,7 @@
     EXPECT_FALSE(mReactor.addHwVsyncTimestamp(newPeriod, std::nullopt, &periodFlushed));
     EXPECT_TRUE(periodFlushed);
 
-    EXPECT_TRUE(mReactor.addPresentFence(generateSignalledFenceWithTime(0)));
+    EXPECT_FALSE(mReactor.addPresentFence(generateSignalledFenceWithTime(0)));
 }
 
 TEST_F(VSyncReactorTest, setPeriodCalledOnceConfirmedChange) {
@@ -463,8 +461,7 @@
 
 TEST_F(VSyncReactorTest, periodChangeWithGivenVsyncPeriod) {
     bool periodFlushed = true;
-    EXPECT_CALL(*mMockTracker, addVsyncTimestamp(_)).Times(2);
-    mReactor.setIgnorePresentFences(true);
+    EXPECT_CALL(*mMockTracker, addVsyncTimestamp(_)).Times(3);
 
     nsecs_t const newPeriod = 5000;
     mReactor.onDisplayModeChanged(displayMode(newPeriod), false);
@@ -476,7 +473,7 @@
     EXPECT_FALSE(mReactor.addHwVsyncTimestamp(newPeriod, newPeriod, &periodFlushed));
     EXPECT_TRUE(periodFlushed);
 
-    EXPECT_TRUE(mReactor.addPresentFence(generateSignalledFenceWithTime(0)));
+    EXPECT_FALSE(mReactor.addPresentFence(generateSignalledFenceWithTime(0)));
 }
 
 TEST_F(VSyncReactorTest, periodIsMeasuredIfIgnoringComposer) {
@@ -486,8 +483,7 @@
                          *mMockTracker, kPendingLimit, true /* supportKernelIdleTimer */);
 
     bool periodFlushed = true;
-    EXPECT_CALL(*mMockTracker, addVsyncTimestamp(_)).Times(4);
-    idleReactor.setIgnorePresentFences(true);
+    EXPECT_CALL(*mMockTracker, addVsyncTimestamp(_)).Times(5);
 
     // First, set the same period, which should only be confirmed when we receive two
     // matching callbacks
@@ -512,7 +508,7 @@
     EXPECT_FALSE(idleReactor.addHwVsyncTimestamp(20000, 5000, &periodFlushed));
     EXPECT_TRUE(periodFlushed);
 
-    EXPECT_TRUE(idleReactor.addPresentFence(generateSignalledFenceWithTime(0)));
+    EXPECT_FALSE(idleReactor.addPresentFence(generateSignalledFenceWithTime(0)));
 }
 
 } // namespace android::scheduler