diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index abfb9c99de6b9..553aad1a43cd7 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -3554,7 +3554,11 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
             return false;
         }
         return mWmService.mDisplayWindowSettings.shouldShowImeLocked(this)
-                || mWmService.mForceDesktopModeOnExternalDisplays;
+                || forceDesktopMode();
+    }
+
+    boolean forceDesktopMode() {
+        return mWmService.mForceDesktopModeOnExternalDisplays && !isDefaultDisplay && !isPrivate();
     }
 
     private void setInputMethodTarget(WindowState target, boolean targetWaitingAnim) {
@@ -4786,7 +4790,7 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
     boolean supportsSystemDecorations() {
         return (mWmService.mDisplayWindowSettings.shouldShowSystemDecorsLocked(this)
                 || (mDisplay.getFlags() & FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS) != 0
-                || mWmService.mForceDesktopModeOnExternalDisplays)
+                || forceDesktopMode())
                 // VR virtual display will be used to run and render 2D app within a VR experience.
                 && mDisplayId != mWmService.mVr2dDisplayId
                 // Do not show system decorations on untrusted virtual display.
diff --git a/services/core/java/com/android/server/wm/DisplayRotation.java b/services/core/java/com/android/server/wm/DisplayRotation.java
index 37ecee8e3db38..1284e009ee3f8 100644
--- a/services/core/java/com/android/server/wm/DisplayRotation.java
+++ b/services/core/java/com/android/server/wm/DisplayRotation.java
@@ -330,10 +330,8 @@ public class DisplayRotation {
         // It's also not likely to rotate a TV screen.
         final boolean isTv = mContext.getPackageManager().hasSystemFeature(
                 PackageManager.FEATURE_LEANBACK);
-        final boolean forceDesktopMode =
-                mService.mForceDesktopModeOnExternalDisplays && !isDefaultDisplay;
         mDefaultFixedToUserRotation =
-                (isCar || isTv || mService.mIsPc || forceDesktopMode)
+                (isCar || isTv || mService.mIsPc || mDisplayContent.forceDesktopMode())
                 // For debug purposes the next line turns this feature off with:
                 // $ adb shell setprop config.override_forced_orient true
                 // $ adb shell wm size reset
diff --git a/services/core/java/com/android/server/wm/DisplayWindowSettings.java b/services/core/java/com/android/server/wm/DisplayWindowSettings.java
index 470a02e5bd449..34b403b18d202 100644
--- a/services/core/java/com/android/server/wm/DisplayWindowSettings.java
+++ b/services/core/java/com/android/server/wm/DisplayWindowSettings.java
@@ -248,7 +248,7 @@ class DisplayWindowSettings {
         writeSettingsIfNeeded(entry, displayInfo);
     }
 
-    private int getWindowingModeLocked(Entry entry, int displayId) {
+    private int getWindowingModeLocked(Entry entry, DisplayContent dc) {
         int windowingMode = entry != null ? entry.mWindowingMode
                 : WindowConfiguration.WINDOWING_MODE_UNDEFINED;
         // This display used to be in freeform, but we don't support freeform anymore, so fall
@@ -259,10 +259,8 @@ class DisplayWindowSettings {
         }
         // No record is present so use default windowing mode policy.
         if (windowingMode == WindowConfiguration.WINDOWING_MODE_UNDEFINED) {
-            final boolean forceDesktopMode = mService.mForceDesktopModeOnExternalDisplays
-                    && displayId != Display.DEFAULT_DISPLAY;
             windowingMode = mService.mAtmService.mSupportsFreeformWindowManagement
-                    && (mService.mIsPc || forceDesktopMode)
+                    && (mService.mIsPc || dc.forceDesktopMode())
                     ? WindowConfiguration.WINDOWING_MODE_FREEFORM
                     : WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
         }
@@ -272,7 +270,7 @@ class DisplayWindowSettings {
     int getWindowingModeLocked(DisplayContent dc) {
         final DisplayInfo displayInfo = dc.getDisplayInfo();
         final Entry entry = getEntry(displayInfo);
-        return getWindowingModeLocked(entry, dc.getDisplayId());
+        return getWindowingModeLocked(entry, dc);
     }
 
     void setWindowingModeLocked(DisplayContent dc, int mode) {
@@ -382,7 +380,7 @@ class DisplayWindowSettings {
         final Entry entry = getOrCreateEntry(displayInfo);
 
         // Setting windowing mode first, because it may override overscan values later.
-        dc.setWindowingMode(getWindowingModeLocked(entry, dc.getDisplayId()));
+        dc.setWindowingMode(getWindowingModeLocked(entry, dc));
 
         dc.getDisplayRotation().restoreSettings(entry.mUserRotationMode,
                 entry.mUserRotation, entry.mFixedToUserRotation);
diff --git a/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java b/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
index dc838f1bb2889..6a84c13901508 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
@@ -28,6 +28,7 @@ import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_USER;
 import static android.os.Build.VERSION_CODES.P;
 import static android.os.Build.VERSION_CODES.Q;
 import static android.view.Display.DEFAULT_DISPLAY;
+import static android.view.Display.FLAG_PRIVATE;
 import static android.view.DisplayCutout.BOUNDS_POSITION_LEFT;
 import static android.view.DisplayCutout.BOUNDS_POSITION_TOP;
 import static android.view.DisplayCutout.fromBoundingRect;
@@ -95,6 +96,7 @@ import android.os.SystemClock;
 import android.platform.test.annotations.Presubmit;
 import android.util.DisplayMetrics;
 import android.view.DisplayCutout;
+import android.view.DisplayInfo;
 import android.view.Gravity;
 import android.view.IDisplayWindowRotationCallback;
 import android.view.IDisplayWindowRotationController;
@@ -1439,6 +1441,29 @@ public class DisplayContentTests extends WindowTestsBase {
         mDisplayContent.ensureActivitiesVisible(null, 0, false, false);
     }
 
+    @Test
+    public void testForceDesktopMode() {
+        mWm.mForceDesktopModeOnExternalDisplays = true;
+        // Not applicable for default display
+        final DisplayContent defaultDisplay = mWm.mRoot.getDefaultDisplay();
+        assertFalse(defaultDisplay.forceDesktopMode());
+
+        // Not applicable for private secondary display.
+        final DisplayInfo displayInfo = new DisplayInfo();
+        displayInfo.copyFrom(mDisplayInfo);
+        displayInfo.flags = FLAG_PRIVATE;
+        final DisplayContent privateDc = createNewDisplay(displayInfo);
+        assertFalse(privateDc.forceDesktopMode());
+
+        // Applicable for public secondary display.
+        final DisplayContent publicDc = createNewDisplay();
+        assertTrue(publicDc.forceDesktopMode());
+
+        // Make sure forceDesktopMode() is false when the force config is disabled.
+        mWm.mForceDesktopModeOnExternalDisplays = false;
+        assertFalse(publicDc.forceDesktopMode());
+    }
+
     private boolean isOptionsPanelAtRight(int displayId) {
         return (mWm.getPreferredOptionsPanelGravity(displayId) & Gravity.RIGHT) == Gravity.RIGHT;
     }