diff --git a/api/current.txt b/api/current.txt
index 3f15b2fc36507..0e87d3d2741c6 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -27533,6 +27533,7 @@ package android.service.notification {
     field public static final int INTERRUPTION_FILTER_ALL = 1; // 0x1
     field public static final int INTERRUPTION_FILTER_NONE = 3; // 0x3
     field public static final int INTERRUPTION_FILTER_PRIORITY = 2; // 0x2
+    field public static final int INTERRUPTION_FILTER_UNKNOWN = 0; // 0x0
     field public static final java.lang.String SERVICE_INTERFACE = "android.service.notification.NotificationListenerService";
   }
 
diff --git a/api/system-current.txt b/api/system-current.txt
index f89c06967e7b7..ce240eef782fe 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -29168,6 +29168,7 @@ package android.service.notification {
     field public static final int INTERRUPTION_FILTER_ALL = 1; // 0x1
     field public static final int INTERRUPTION_FILTER_NONE = 3; // 0x3
     field public static final int INTERRUPTION_FILTER_PRIORITY = 2; // 0x2
+    field public static final int INTERRUPTION_FILTER_UNKNOWN = 0; // 0x0
     field public static final java.lang.String SERVICE_INTERFACE = "android.service.notification.NotificationListenerService";
     field public static final int TRIM_FULL = 0; // 0x0
     field public static final int TRIM_LIGHT = 1; // 0x1
diff --git a/core/java/android/service/notification/NotificationListenerService.java b/core/java/android/service/notification/NotificationListenerService.java
index 3d39b188fcb6a..0860153988ec9 100644
--- a/core/java/android/service/notification/NotificationListenerService.java
+++ b/core/java/android/service/notification/NotificationListenerService.java
@@ -77,6 +77,14 @@ public abstract class NotificationListenerService extends Service {
      */
     public static final int INTERRUPTION_FILTER_NONE = 3;
 
+    /** {@link #getCurrentInterruptionFilter() Interruption filter} constant - returned when
+     * the value is unavailable for any reason.  For example, before the notification listener
+     * is connected.
+     *
+     * {@see #onListenerConnected()}
+     */
+    public static final int INTERRUPTION_FILTER_UNKNOWN = 0;
+
     /** {@link #getCurrentListenerHints() Listener hints} constant - the primary device UI
      * should disable notification sound, vibrating and other visual or aural effects.
      * This does not change the interruption filter, only the effects. **/
@@ -473,15 +481,16 @@ public abstract class NotificationListenerService extends Service {
      * <p>
      * Listen for updates using {@link #onInterruptionFilterChanged(int)}.
      *
-     * @return One of the INTERRUPTION_FILTER_ constants, or 0 on errors.
+     * @return One of the INTERRUPTION_FILTER_ constants, or INTERRUPTION_FILTER_UNKNOWN when
+     * unavailable.
      */
     public final int getCurrentInterruptionFilter() {
-        if (!isBound()) return 0;
+        if (!isBound()) return INTERRUPTION_FILTER_UNKNOWN;
         try {
             return getNotificationInterface().getInterruptionFilterFromListener(mWrapper);
         } catch (android.os.RemoteException ex) {
             Log.v(TAG, "Unable to contact notification manager", ex);
-            return 0;
+            return INTERRUPTION_FILTER_UNKNOWN;
         }
     }
 
diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index 02cacd9affb66..c5672640f6216 100644
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -207,7 +207,7 @@ public class NotificationManagerService extends SystemService {
     private final ArraySet<ManagedServiceInfo> mListenersDisablingEffects = new ArraySet<>();
     private ComponentName mEffectsSuppressor;
     private int mListenerHints;  // right now, all hints are global
-    private int mInterruptionFilter;  // current ZEN mode as communicated to listeners
+    private int mInterruptionFilter = NotificationListenerService.INTERRUPTION_FILTER_UNKNOWN;
 
     // for enabling and disabling notification pulse behavior
     private boolean mScreenOn = true;