diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index dafa0ad..993fcf8 100644
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -6092,4 +6092,8 @@
 
     <!-- Whether to show weather on the lock screen by default. -->
     <bool name="config_lockscreenWeatherEnabledByDefault">false</bool>
+
+    <!-- Whether we should persist the brightness value in nits for the default display even if
+         the underlying display device changes. -->
+    <bool name="config_persistBrightnessNitsForDefaultDisplay">false</bool>
 </resources>
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index 591ba5f..c04c322 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -2282,6 +2282,7 @@
   <java-symbol type="bool" name="config_preventImeStartupUnlessTextEditor" />
   <java-symbol type="array" name="config_nonPreemptibleInputMethods" />
   <java-symbol type="bool" name="config_enhancedConfirmationModeEnabled" />
+  <java-symbol type="bool" name="config_persistBrightnessNitsForDefaultDisplay" />
 
   <java-symbol type="layout" name="resolver_list" />
   <java-symbol type="id" name="resolver_list" />
diff --git a/services/core/java/com/android/server/display/AutomaticBrightnessController.java b/services/core/java/com/android/server/display/AutomaticBrightnessController.java
index 8b579ac..2292d9b 100644
--- a/services/core/java/com/android/server/display/AutomaticBrightnessController.java
+++ b/services/core/java/com/android/server/display/AutomaticBrightnessController.java
@@ -1127,6 +1127,14 @@
         }
     }
 
+    public float convertToFloatScale(float nits) {
+        if (mCurrentBrightnessMapper != null) {
+            return mCurrentBrightnessMapper.convertToFloatScale(nits);
+        } else {
+            return PowerManager.BRIGHTNESS_INVALID_FLOAT;
+        }
+    }
+
     public void recalculateSplines(boolean applyAdjustment, float[] adjustment) {
         mCurrentBrightnessMapper.recalculateSplines(applyAdjustment, adjustment);
 
diff --git a/services/core/java/com/android/server/display/BrightnessMappingStrategy.java b/services/core/java/com/android/server/display/BrightnessMappingStrategy.java
index 3fc50c4..d047183 100644
--- a/services/core/java/com/android/server/display/BrightnessMappingStrategy.java
+++ b/services/core/java/com/android/server/display/BrightnessMappingStrategy.java
@@ -322,6 +322,14 @@
     public abstract float convertToNits(float brightness);
 
     /**
+     * Converts the provided nit value to a float scale value if possible.
+     *
+     * Returns {@link PowerManager.BRIGHTNESS_INVALID_FLOAT} if there's no available mapping for
+     * the nits to float scale.
+     */
+    public abstract float convertToFloatScale(float nits);
+
+    /**
      * Adds a user interaction data point to the brightness mapping.
      *
      * This data point <b>must</b> exist on the brightness curve as a result of this call. This is
@@ -671,6 +679,11 @@
         }
 
         @Override
+        public float convertToFloatScale(float nits) {
+            return PowerManager.BRIGHTNESS_INVALID_FLOAT;
+        }
+
+        @Override
         public void addUserDataPoint(float lux, float brightness) {
             float unadjustedBrightness = getUnadjustedBrightness(lux);
             if (mLoggingEnabled) {
@@ -913,6 +926,11 @@
         }
 
         @Override
+        public float convertToFloatScale(float nits) {
+            return mNitsToBrightnessSpline.interpolate(nits);
+        }
+
+        @Override
         public void addUserDataPoint(float lux, float brightness) {
             float unadjustedBrightness = getUnadjustedBrightness(lux);
             if (mLoggingEnabled) {
diff --git a/services/core/java/com/android/server/display/BrightnessSetting.java b/services/core/java/com/android/server/display/BrightnessSetting.java
index 7448611..9982d2e 100644
--- a/services/core/java/com/android/server/display/BrightnessSetting.java
+++ b/services/core/java/com/android/server/display/BrightnessSetting.java
@@ -117,6 +117,23 @@
         }
     }
 
+    /**
+     * @return The brightness for the default display in nits. Used when the underlying display
+     * device has changed but we want to persist the nit value.
+     */
+    float getBrightnessNitsForDefaultDisplay() {
+        return mPersistentDataStore.getBrightnessNitsForDefaultDisplay();
+    }
+
+    /**
+     * Set brightness in nits for the default display. Used when we want to persist the nit value
+     * even if the underlying display device changes.
+     * @param nits The brightness value in nits
+     */
+    void setBrightnessNitsForDefaultDisplay(float nits) {
+        mPersistentDataStore.setBrightnessNitsForDefaultDisplay(nits);
+    }
+
     private void notifyListeners(float brightness) {
         for (BrightnessSettingListener l : mListeners) {
             l.onBrightnessChanged(brightness);
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index c869fcd..2584800 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -233,6 +233,10 @@
     // True if should use light sensor to automatically determine doze screen brightness.
     private final boolean mAllowAutoBrightnessWhileDozingConfig;
 
+    // True if we want to persist the brightness value in nits even if the underlying display
+    // device changes.
+    private final boolean mPersistBrightnessNitsForDefaultDisplay;
+
     // True if the brightness config has changed and the short-term model needs to be reset
     private boolean mShouldResetShortTermModel;
 
@@ -583,6 +587,9 @@
         mAllowAutoBrightnessWhileDozingConfig = resources.getBoolean(
                 com.android.internal.R.bool.config_allowAutoBrightnessWhileDozing);
 
+        mPersistBrightnessNitsForDefaultDisplay = resources.getBoolean(
+                com.android.internal.R.bool.config_persistBrightnessNitsForDefaultDisplay);
+
         mDisplayDeviceConfig = logicalDisplay.getPrimaryDisplayDeviceLocked()
                 .getDisplayDeviceConfig();
 
@@ -651,7 +658,7 @@
 
         loadProximitySensor();
 
-        mCurrentScreenBrightnessSetting = getScreenBrightnessSetting();
+        loadNitBasedBrightnessSetting();
         mScreenBrightnessForVr = getScreenBrightnessForVrSetting();
         mAutoBrightnessAdjustment = getAutoBrightnessAdjustmentSetting();
         mTemporaryScreenBrightness = PowerManager.BRIGHTNESS_INVALID_FLOAT;
@@ -829,6 +836,7 @@
                 mDisplayStatsId = mUniqueDisplayId.hashCode();
                 mDisplayDeviceConfig = config;
                 loadFromDisplayDeviceConfig(token, info, hbmMetadata);
+                loadNitBasedBrightnessSetting();
 
                 /// Since the underlying display-device changed, we really don't know the
                 // last command that was sent to change it's state. Lets assume it is unknown so
@@ -2498,10 +2506,33 @@
         return clampScreenBrightnessForVr(brightnessFloat);
     }
 
+    private void loadNitBasedBrightnessSetting() {
+        if (mDisplayId == Display.DEFAULT_DISPLAY && mPersistBrightnessNitsForDefaultDisplay) {
+            float brightnessNitsForDefaultDisplay =
+                    mBrightnessSetting.getBrightnessNitsForDefaultDisplay();
+            if (brightnessNitsForDefaultDisplay >= 0) {
+                float brightnessForDefaultDisplay = convertToFloatScale(
+                        brightnessNitsForDefaultDisplay);
+                if (isValidBrightnessValue(brightnessForDefaultDisplay)) {
+                    mBrightnessSetting.setBrightness(brightnessForDefaultDisplay);
+                    mCurrentScreenBrightnessSetting = brightnessForDefaultDisplay;
+                    return;
+                }
+            }
+        }
+        mCurrentScreenBrightnessSetting = getScreenBrightnessSetting();
+    }
+
     void setBrightness(float brightnessValue) {
         // Update the setting, which will eventually call back into DPC to have us actually update
         // the display with the new value.
         mBrightnessSetting.setBrightness(brightnessValue);
+        if (mDisplayId == Display.DEFAULT_DISPLAY && mPersistBrightnessNitsForDefaultDisplay) {
+            float nits = convertToNits(brightnessValue);
+            if (nits >= 0) {
+                mBrightnessSetting.setBrightnessNitsForDefaultDisplay(nits);
+            }
+        }
     }
 
     void onBootCompleted() {
@@ -2514,7 +2545,7 @@
             return;
         }
         setCurrentScreenBrightness(brightnessValue);
-        mBrightnessSetting.setBrightness(brightnessValue);
+        setBrightness(brightnessValue);
     }
 
     private void setCurrentScreenBrightness(float brightnessValue) {
@@ -2593,6 +2624,13 @@
         return mAutomaticBrightnessController.convertToNits(brightness);
     }
 
+    private float convertToFloatScale(float nits) {
+        if (mAutomaticBrightnessController == null) {
+            return PowerManager.BRIGHTNESS_INVALID_FLOAT;
+        }
+        return mAutomaticBrightnessController.convertToFloatScale(nits);
+    }
+
     @GuardedBy("mLock")
     private void updatePendingProximityRequestsLocked() {
         mWaitingForNegativeProximity |= mPendingWaitForNegativeProximityLocked;
@@ -2690,25 +2728,27 @@
         pw.println("  mScreenBrightnessForVrRangeMaximum=" + mScreenBrightnessForVrRangeMaximum);
         pw.println("  mScreenBrightnessForVrDefault=" + mScreenBrightnessForVrDefault);
         pw.println("  mUseSoftwareAutoBrightnessConfig=" + mUseSoftwareAutoBrightnessConfig);
-        pw.println("  mAllowAutoBrightnessWhileDozingConfig=" +
-                mAllowAutoBrightnessWhileDozingConfig);
+        pw.println("  mAllowAutoBrightnessWhileDozingConfig="
+                + mAllowAutoBrightnessWhileDozingConfig);
+        pw.println("  mPersistBrightnessNitsForDefaultDisplay="
+                + mPersistBrightnessNitsForDefaultDisplay);
         pw.println("  mSkipScreenOnBrightnessRamp=" + mSkipScreenOnBrightnessRamp);
         pw.println("  mColorFadeFadesConfig=" + mColorFadeFadesConfig);
         pw.println("  mColorFadeEnabled=" + mColorFadeEnabled);
         synchronized (mCachedBrightnessInfo) {
-            pw.println("  mCachedBrightnessInfo.brightness=" +
-                    mCachedBrightnessInfo.brightness.value);
-            pw.println("  mCachedBrightnessInfo.adjustedBrightness=" +
-                    mCachedBrightnessInfo.adjustedBrightness.value);
-            pw.println("  mCachedBrightnessInfo.brightnessMin=" +
-                    mCachedBrightnessInfo.brightnessMin.value);
-            pw.println("  mCachedBrightnessInfo.brightnessMax=" +
-                    mCachedBrightnessInfo.brightnessMax.value);
+            pw.println("  mCachedBrightnessInfo.brightness="
+                    + mCachedBrightnessInfo.brightness.value);
+            pw.println("  mCachedBrightnessInfo.adjustedBrightness="
+                    + mCachedBrightnessInfo.adjustedBrightness.value);
+            pw.println("  mCachedBrightnessInfo.brightnessMin="
+                    + mCachedBrightnessInfo.brightnessMin.value);
+            pw.println("  mCachedBrightnessInfo.brightnessMax="
+                    + mCachedBrightnessInfo.brightnessMax.value);
             pw.println("  mCachedBrightnessInfo.hbmMode=" + mCachedBrightnessInfo.hbmMode.value);
-            pw.println("  mCachedBrightnessInfo.hbmTransitionPoint=" +
-                    mCachedBrightnessInfo.hbmTransitionPoint.value);
-            pw.println("  mCachedBrightnessInfo.brightnessMaxReason =" +
-                    mCachedBrightnessInfo.brightnessMaxReason.value);
+            pw.println("  mCachedBrightnessInfo.hbmTransitionPoint="
+                    + mCachedBrightnessInfo.hbmTransitionPoint.value);
+            pw.println("  mCachedBrightnessInfo.brightnessMaxReason ="
+                    + mCachedBrightnessInfo.brightnessMaxReason.value);
         }
         pw.println("  mDisplayBlanksAfterDozeConfig=" + mDisplayBlanksAfterDozeConfig);
         pw.println("  mBrightnessBucketsInDozeConfig=" + mBrightnessBucketsInDozeConfig);
diff --git a/services/core/java/com/android/server/display/PersistentDataStore.java b/services/core/java/com/android/server/display/PersistentDataStore.java
index 73131a1..a8e0d58 100644
--- a/services/core/java/com/android/server/display/PersistentDataStore.java
+++ b/services/core/java/com/android/server/display/PersistentDataStore.java
@@ -94,6 +94,7 @@
  *          &lt;/brightness-curve>
  *      &lt;/brightness-configuration>
  *  &lt;/brightness-configurations>
+ *  &lt;brightness-nits-for-default-display>600&lt;/brightness-nits-for-default-display>
  * &lt;/display-manager-state>
  * </code>
  *
@@ -130,6 +131,9 @@
     private static final String TAG_RESOLUTION_HEIGHT = "resolution-height";
     private static final String TAG_REFRESH_RATE = "refresh-rate";
 
+    private static final String TAG_BRIGHTNESS_NITS_FOR_DEFAULT_DISPLAY =
+            "brightness-nits-for-default-display";
+
     // Remembered Wifi display devices.
     private ArrayList<WifiDisplay> mRememberedWifiDisplays = new ArrayList<WifiDisplay>();
 
@@ -137,6 +141,8 @@
     private final HashMap<String, DisplayState> mDisplayStates =
             new HashMap<String, DisplayState>();
 
+    private float mBrightnessNitsForDefaultDisplay = -1;
+
     // Display values which should be stable across the device's lifetime.
     private final StableDeviceValues mStableDeviceValues = new StableDeviceValues();
 
@@ -312,6 +318,19 @@
         return false;
     }
 
+    public float getBrightnessNitsForDefaultDisplay() {
+        return mBrightnessNitsForDefaultDisplay;
+    }
+
+    public boolean setBrightnessNitsForDefaultDisplay(float nits) {
+        if (nits != mBrightnessNitsForDefaultDisplay) {
+            mBrightnessNitsForDefaultDisplay = nits;
+            setDirty();
+            return true;
+        }
+        return false;
+    }
+
     public boolean setUserPreferredRefreshRate(DisplayDevice displayDevice, float refreshRate) {
         final String displayDeviceUniqueId = displayDevice.getUniqueId();
         if (!displayDevice.hasStableUniqueId() || displayDeviceUniqueId == null) {
@@ -513,6 +532,10 @@
             if (parser.getName().equals(TAG_BRIGHTNESS_CONFIGURATIONS)) {
                 mGlobalBrightnessConfigurations.loadFromXml(parser);
             }
+            if (parser.getName().equals(TAG_BRIGHTNESS_NITS_FOR_DEFAULT_DISPLAY)) {
+                String value = parser.nextText();
+                mBrightnessNitsForDefaultDisplay = Float.parseFloat(value);
+            }
         }
     }
 
@@ -592,6 +615,9 @@
         serializer.startTag(null, TAG_BRIGHTNESS_CONFIGURATIONS);
         mGlobalBrightnessConfigurations.saveToXml(serializer);
         serializer.endTag(null, TAG_BRIGHTNESS_CONFIGURATIONS);
+        serializer.startTag(null, TAG_BRIGHTNESS_NITS_FOR_DEFAULT_DISPLAY);
+        serializer.text(Float.toString(mBrightnessNitsForDefaultDisplay));
+        serializer.endTag(null, TAG_BRIGHTNESS_NITS_FOR_DEFAULT_DISPLAY);
         serializer.endTag(null, TAG_DISPLAY_MANAGER_STATE);
         serializer.endDocument();
     }
@@ -615,6 +641,7 @@
         mStableDeviceValues.dump(pw, "      ");
         pw.println("  GlobalBrightnessConfigurations:");
         mGlobalBrightnessConfigurations.dump(pw, "      ");
+        pw.println("  mBrightnessNitsForDefaultDisplay=" + mBrightnessNitsForDefaultDisplay);
     }
 
     private static final class DisplayState {
diff --git a/services/tests/servicestests/src/com/android/server/display/PersistentDataStoreTest.java b/services/tests/servicestests/src/com/android/server/display/PersistentDataStoreTest.java
index 35a677e..817b245 100644
--- a/services/tests/servicestests/src/com/android/server/display/PersistentDataStoreTest.java
+++ b/services/tests/servicestests/src/com/android/server/display/PersistentDataStoreTest.java
@@ -377,6 +377,33 @@
         assertTrue(Float.isNaN(mDataStore.getBrightness(testDisplayDevice)));
     }
 
+    @Test
+    public void testStoreAndRestoreBrightnessNitsForDefaultDisplay() {
+        float brightnessNitsForDefaultDisplay = 190;
+        mDataStore.loadIfNeeded();
+        mDataStore.setBrightnessNitsForDefaultDisplay(brightnessNitsForDefaultDisplay);
+
+        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        mInjector.setWriteStream(baos);
+        mDataStore.saveIfNeeded();
+        mTestLooper.dispatchAll();
+        assertTrue(mInjector.wasWriteSuccessful());
+        TestInjector newInjector = new TestInjector();
+        PersistentDataStore newDataStore = new PersistentDataStore(newInjector);
+        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+        newInjector.setReadStream(bais);
+        newDataStore.loadIfNeeded();
+        assertEquals(brightnessNitsForDefaultDisplay,
+                mDataStore.getBrightnessNitsForDefaultDisplay(), 0);
+        assertEquals(brightnessNitsForDefaultDisplay,
+                newDataStore.getBrightnessNitsForDefaultDisplay(), 0);
+    }
+
+    @Test
+    public void testInitialBrightnessNitsForDefaultDisplay() {
+        mDataStore.loadIfNeeded();
+        assertEquals(-1, mDataStore.getBrightnessNitsForDefaultDisplay(), 0);
+    }
 
     public class TestInjector extends PersistentDataStore.Injector {
         private InputStream mReadStream;