diff --git a/services/core/java/com/android/server/notification/ZenLog.java b/services/core/java/com/android/server/notification/ZenLog.java
index 1050835a98127..7d7f3a96595c2 100644
--- a/services/core/java/com/android/server/notification/ZenLog.java
+++ b/services/core/java/com/android/server/notification/ZenLog.java
@@ -65,6 +65,7 @@ public class ZenLog {
     private static final int TYPE_LISTENER_HINTS_CHANGED = 15;
     private static final int TYPE_SET_NOTIFICATION_POLICY = 16;
     private static final int TYPE_SET_CONSOLIDATED_ZEN_POLICY = 17;
+    private static final int TYPE_MATCHES_CALL_FILTER = 18;
 
     private static int sNext;
     private static int sSize;
@@ -166,6 +167,13 @@ public class ZenLog {
             + hintsToString(newHints) + ",listeners=" + listenerCount);
     }
 
+    /*
+     * Trace calls to matchesCallFilter with the result of the call and the reason for the result.
+     */
+    public static void traceMatchesCallFilter(boolean result, String reason) {
+        append(TYPE_MATCHES_CALL_FILTER, "result=" + result + ", reason=" + reason);
+    }
+
     private static String subscribeResult(IConditionProvider provider, RemoteException e) {
         return provider == null ? "no provider" : e != null ? e.getMessage() : "ok";
     }
@@ -189,6 +197,7 @@ public class ZenLog {
             case TYPE_LISTENER_HINTS_CHANGED: return "listener_hints_changed";
             case TYPE_SET_NOTIFICATION_POLICY: return "set_notification_policy";
             case TYPE_SET_CONSOLIDATED_ZEN_POLICY: return "set_consolidated_policy";
+            case TYPE_MATCHES_CALL_FILTER: return "matches_call_filter";
             default: return "unknown";
         }
     }
diff --git a/services/core/java/com/android/server/notification/ZenModeFiltering.java b/services/core/java/com/android/server/notification/ZenModeFiltering.java
index 0f526d4d63431..b186f610d4988 100644
--- a/services/core/java/com/android/server/notification/ZenModeFiltering.java
+++ b/services/core/java/com/android/server/notification/ZenModeFiltering.java
@@ -89,20 +89,34 @@ public class ZenModeFiltering {
     public static boolean matchesCallFilter(Context context, int zen, NotificationManager.Policy
             consolidatedPolicy, UserHandle userHandle, Bundle extras,
             ValidateNotificationPeople validator, int contactsTimeoutMs, float timeoutAffinity) {
-        if (zen == Global.ZEN_MODE_NO_INTERRUPTIONS) return false; // nothing gets through
-        if (zen == Global.ZEN_MODE_ALARMS) return false; // not an alarm
+        if (zen == Global.ZEN_MODE_NO_INTERRUPTIONS) {
+            ZenLog.traceMatchesCallFilter(false, "no interruptions");
+            return false; // nothing gets through
+        }
+        if (zen == Global.ZEN_MODE_ALARMS) {
+            ZenLog.traceMatchesCallFilter(false, "alarms only");
+            return false; // not an alarm
+        }
         if (zen == Global.ZEN_MODE_IMPORTANT_INTERRUPTIONS) {
             if (consolidatedPolicy.allowRepeatCallers()
                     && REPEAT_CALLERS.isRepeat(context, extras)) {
+                ZenLog.traceMatchesCallFilter(true, "repeat caller");
                 return true;
             }
-            if (!consolidatedPolicy.allowCalls()) return false; // no other calls get through
+            if (!consolidatedPolicy.allowCalls()) {
+                ZenLog.traceMatchesCallFilter(false, "calls not allowed");
+                return false; // no other calls get through
+            }
             if (validator != null) {
                 final float contactAffinity = validator.getContactAffinity(userHandle, extras,
                         contactsTimeoutMs, timeoutAffinity);
-                return audienceMatches(consolidatedPolicy.allowCallsFrom(), contactAffinity);
+                boolean match =
+                        audienceMatches(consolidatedPolicy.allowCallsFrom(), contactAffinity);
+                ZenLog.traceMatchesCallFilter(match, "contact affinity " + contactAffinity);
+                return match;
             }
         }
+        ZenLog.traceMatchesCallFilter(true, "no restrictions");
         return true;
     }