diff --git a/services/core/java/com/android/server/display/BrightnessRangeController.java b/services/core/java/com/android/server/display/BrightnessRangeController.java
index dc0e80c..9b37418 100644
--- a/services/core/java/com/android/server/display/BrightnessRangeController.java
+++ b/services/core/java/com/android/server/display/BrightnessRangeController.java
@@ -19,7 +19,6 @@
 import android.hardware.display.BrightnessInfo;
 import android.os.Handler;
 import android.os.IBinder;
-import android.os.PowerManager;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.server.display.brightness.clamper.HdrClamper;
@@ -148,9 +147,7 @@
 
     float getHdrBrightnessValue() {
         float hdrBrightness = mHbmController.getHdrBrightnessValue();
-        float brightnessMax = mUseHdrClamper ? mHdrClamper.getMaxBrightness()
-                : PowerManager.BRIGHTNESS_MAX;
-        return Math.min(hdrBrightness, brightnessMax);
+        return mUseHdrClamper ? mHdrClamper.clamp(hdrBrightness) : hdrBrightness;
     }
 
     float getTransitionPoint() {
diff --git a/services/core/java/com/android/server/display/brightness/clamper/HdrClamper.java b/services/core/java/com/android/server/display/brightness/clamper/HdrClamper.java
index f1cb66c..902daa4 100644
--- a/services/core/java/com/android/server/display/brightness/clamper/HdrClamper.java
+++ b/services/core/java/com/android/server/display/brightness/clamper/HdrClamper.java
@@ -59,6 +59,11 @@
 
     private boolean mAutoBrightnessEnabled = false;
 
+    /**
+     * Indicates that maxBrightness is changed, and we should use slow transition
+     */
+    private boolean mUseSlowTransition = false;
+
     public HdrClamper(BrightnessClamperController.ClamperChangeListener clamperChangeListener,
             Handler handler) {
         this(clamperChangeListener, handler, new Injector());
@@ -72,6 +77,7 @@
         mDebouncer = () -> {
             mTransitionRate = mDesiredTransitionRate;
             mMaxBrightness = mDesiredMaxBrightness;
+            mUseSlowTransition = true;
             mClamperChangeListener.onChanged();
         };
         mHdrListener = injector.getHdrListener((visible) -> {
@@ -80,14 +86,24 @@
         }, handler);
     }
 
-    // Called in same looper: mHandler.getLooper()
+    /**
+     * Applies clamping
+     * Called in same looper: mHandler.getLooper()
+     */
+    public float clamp(float brightness) {
+        return Math.min(brightness, mMaxBrightness);
+    }
+
+    @VisibleForTesting
     public float getMaxBrightness() {
         return mMaxBrightness;
     }
 
     // Called in same looper: mHandler.getLooper()
     public float getTransitionRate() {
-        return mTransitionRate;
+        float expectedTransitionRate =  mUseSlowTransition ? mTransitionRate : -1;
+        mUseSlowTransition = false;
+        return  expectedTransitionRate;
     }
 
     /**
@@ -173,7 +189,8 @@
         mMaxBrightness = PowerManager.BRIGHTNESS_MAX;
         mDesiredMaxBrightness = PowerManager.BRIGHTNESS_MAX;
         mDesiredTransitionRate = -1f;
-        mTransitionRate = 1f;
+        mTransitionRate = -1f;
+        mUseSlowTransition = false;
         mClamperChangeListener.onChanged();
     }
 
diff --git a/services/tests/displayservicetests/src/com/android/server/display/DisplayPowerControllerTest.java b/services/tests/displayservicetests/src/com/android/server/display/DisplayPowerControllerTest.java
index de93914..78ebdb1 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/DisplayPowerControllerTest.java
+++ b/services/tests/displayservicetests/src/com/android/server/display/DisplayPowerControllerTest.java
@@ -1312,7 +1312,7 @@
         when(mHolder.hbmController.getHighBrightnessMode()).thenReturn(
                 BrightnessInfo.HIGH_BRIGHTNESS_MODE_HDR);
         when(mHolder.hbmController.getHdrBrightnessValue()).thenReturn(PowerManager.BRIGHTNESS_MAX);
-        when(mHolder.hdrClamper.getMaxBrightness()).thenReturn(clampedBrightness);
+        when(mHolder.hdrClamper.clamp(PowerManager.BRIGHTNESS_MAX)).thenReturn(clampedBrightness);
         when(mHolder.hdrClamper.getTransitionRate()).thenReturn(transitionRate);
 
         mHolder.dpc.requestPowerState(dpr, /* waitForNegativeProximity= */ false);
diff --git a/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/HdrClamperTest.java b/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/HdrClamperTest.java
index 39ffe5b..c785ea6 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/HdrClamperTest.java
+++ b/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/HdrClamperTest.java
@@ -221,6 +221,18 @@
         assertEquals(0.04f, mHdrClamper.getTransitionRate(), FLOAT_TOLERANCE);
     }
 
+    @Test
+    public void testCalmper_transitionRateOverriddenByOtherRequest() {
+        mHdrClamper.onAmbientLuxChange(499);
+
+        mClock.fastForward(3000);
+        mTestHandler.timeAdvance();
+        assertEquals(0.6f, mHdrClamper.getMaxBrightness(), FLOAT_TOLERANCE);
+        assertEquals(0.04, mHdrClamper.getTransitionRate(), FLOAT_TOLERANCE);
+        // getTransitionRate should reset transitionRate
+        assertEquals(-1f, mHdrClamper.getTransitionRate(), FLOAT_TOLERANCE);
+    }
+
     // MsgInfo.sendTime is calculated first by adding SystemClock.uptimeMillis()
     // (in Handler.sendMessageDelayed) and then by subtracting SystemClock.uptimeMillis()
     // (in TestHandler.sendMessageAtTime, there might be several milliseconds difference between