diff --git a/media/java/android/media/MediaRoute2ProviderService.java b/media/java/android/media/MediaRoute2ProviderService.java
index fb95e98ebf477..72162c44ec292 100644
--- a/media/java/android/media/MediaRoute2ProviderService.java
+++ b/media/java/android/media/MediaRoute2ProviderService.java
@@ -519,6 +519,7 @@ public abstract class MediaRoute2ProviderService extends Service {
                     requestCreateSession));
         }
 
+        //TODO: Ignore requests with unknown session ID.
         @Override
         public void selectRoute(long requestId, String sessionId, String routeId) {
             if (!checkCallerisSystem()) {
diff --git a/media/java/android/media/MediaRouter2.java b/media/java/android/media/MediaRouter2.java
index 2c65cc4440a44..7d14ef5542cc7 100644
--- a/media/java/android/media/MediaRouter2.java
+++ b/media/java/android/media/MediaRouter2.java
@@ -604,7 +604,8 @@ public final class MediaRouter2 {
 
         RoutingController oldController = getCurrentController();
         if (!oldController.releaseInternal(
-                /* shouldReleaseSession= */ true, /* shouldNotifyStop= */ false)) {
+                /* shouldReleaseSession= */ matchingRequest != null,
+                /* shouldNotifyStop= */ false)) {
             // Could not release the controller since it was just released by other thread.
             oldController = getSystemController();
         }
diff --git a/media/java/android/media/MediaRouter2Manager.java b/media/java/android/media/MediaRouter2Manager.java
index 3b570b60ff24d..5d61dd06c7920 100644
--- a/media/java/android/media/MediaRouter2Manager.java
+++ b/media/java/android/media/MediaRouter2Manager.java
@@ -314,7 +314,6 @@ public final class MediaRouter2Manager {
 
         //TODO: Ignore unknown route.
         if (sessionInfo.getTransferableRoutes().contains(route.getId())) {
-            //TODO: callbacks must be called after this.
             transferToRoute(sessionInfo, route);
             return;
         }
@@ -340,7 +339,6 @@ public final class MediaRouter2Manager {
             } catch (RemoteException ex) {
                 Log.e(TAG, "Unable to select media route", ex);
             }
-            releaseSession(sessionInfo);
         }
     }
 
@@ -489,6 +487,7 @@ public final class MediaRouter2Manager {
             notifyTransferFailed(matchingRequest.mOldSessionInfo, requestedRoute);
             return;
         }
+        releaseSession(matchingRequest.mOldSessionInfo);
         notifyTransferred(matchingRequest.mOldSessionInfo, sessionInfo);
     }
 
diff --git a/services/core/java/com/android/server/media/MediaRouter2ServiceImpl.java b/services/core/java/com/android/server/media/MediaRouter2ServiceImpl.java
index d8bf9edee2b7a..5e865e7cb7153 100644
--- a/services/core/java/com/android/server/media/MediaRouter2ServiceImpl.java
+++ b/services/core/java/com/android/server/media/MediaRouter2ServiceImpl.java
@@ -1574,8 +1574,15 @@ class MediaRouter2ServiceImpl {
             }
 
             // Succeeded
-            notifySessionCreatedToRouter(matchingRequest.mRouterRecord,
-                    toOriginalRequestId(uniqueRequestId), sessionInfo);
+            if (sessionInfo.isSystemSession()
+                    && !matchingRequest.mRouterRecord.mHasModifyAudioRoutingPermission) {
+                notifySessionCreatedToRouter(matchingRequest.mRouterRecord,
+                        toOriginalRequestId(uniqueRequestId),
+                        mSystemProvider.getDefaultSessionInfo());
+            } else {
+                notifySessionCreatedToRouter(matchingRequest.mRouterRecord,
+                        toOriginalRequestId(uniqueRequestId), sessionInfo);
+            }
             mSessionToRouterMap.put(sessionInfo.getId(), routerRecord);
         }
 
diff --git a/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java b/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java
index 41d7fff52a911..b585b49928cd4 100644
--- a/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java
+++ b/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java
@@ -36,6 +36,7 @@ import android.media.IAudioRoutesObserver;
 import android.media.IAudioService;
 import android.media.MediaRoute2Info;
 import android.media.MediaRoute2ProviderInfo;
+import android.media.MediaRoute2ProviderService;
 import android.media.RouteDiscoveryPreference;
 import android.media.RoutingSessionInfo;
 import android.os.Bundle;
@@ -47,6 +48,7 @@ import android.text.TextUtils;
 import android.util.Log;
 
 import com.android.internal.R;
+import com.android.internal.annotations.GuardedBy;
 
 import java.util.Objects;
 
@@ -80,6 +82,10 @@ class SystemMediaRoute2Provider extends MediaRoute2Provider {
     RoutingSessionInfo mDefaultSessionInfo;
     final AudioRoutesInfo mCurAudioRoutesInfo = new AudioRoutesInfo();
 
+    private final Object mRequestLock = new Object();
+    @GuardedBy("mRequestLock")
+    private volatile SessionCreationRequest mPendingSessionCreationRequest;
+
     final IAudioRoutesObserver.Stub mAudioRoutesObserver = new IAudioRoutesObserver.Stub() {
         @Override
         public void dispatchAudioRoutesChanged(final AudioRoutesInfo newRoutes) {
@@ -135,10 +141,27 @@ class SystemMediaRoute2Provider extends MediaRoute2Provider {
     @Override
     public void requestCreateSession(long requestId, String packageName, String routeId,
             Bundle sessionHints) {
+        // Assume a router without MODIFY_AUDIO_ROUTING permission can't request with
+        // a route ID different from the default route ID. The service should've filtered.
+        if (TextUtils.equals(routeId, DEFAULT_ROUTE_ID)) {
+            mCallback.onSessionCreated(this, requestId, mDefaultSessionInfo);
+            return;
+        }
+        if (TextUtils.equals(routeId, mSelectedRouteId)) {
+            mCallback.onSessionCreated(this, requestId, mSessionInfos.get(0));
+            return;
+        }
+
+        synchronized (mRequestLock) {
+            // Handle the previous request as a failure if exists.
+            if (mPendingSessionCreationRequest != null) {
+                mCallback.onRequestFailed(this, mPendingSessionCreationRequest.mRequestId,
+                        MediaRoute2ProviderService.REASON_UNKNOWN_ERROR);
+            }
+            mPendingSessionCreationRequest = new SessionCreationRequest(requestId, routeId);
+        }
 
         transferToRoute(requestId, SYSTEM_SESSION_ID, routeId);
-        mCallback.onSessionCreated(this, requestId, mSessionInfos.get(0));
-        //TODO: We should call after the session info is changed.
     }
 
     @Override
@@ -280,6 +303,24 @@ class SystemMediaRoute2Provider extends MediaRoute2Provider {
             }
 
             RoutingSessionInfo newSessionInfo = builder.setProviderId(mUniqueId).build();
+
+            if (mPendingSessionCreationRequest != null) {
+                SessionCreationRequest sessionCreationRequest;
+                synchronized (mRequestLock) {
+                    sessionCreationRequest = mPendingSessionCreationRequest;
+                    mPendingSessionCreationRequest = null;
+                }
+                if (sessionCreationRequest != null) {
+                    if (TextUtils.equals(mSelectedRouteId, sessionCreationRequest.mRouteId)) {
+                        mCallback.onSessionCreated(this,
+                                sessionCreationRequest.mRequestId, newSessionInfo);
+                    } else {
+                        mCallback.onRequestFailed(this, sessionCreationRequest.mRequestId,
+                                MediaRoute2ProviderService.REASON_UNKNOWN_ERROR);
+                    }
+                }
+            }
+
             if (Objects.equals(oldSessionInfo, newSessionInfo)) {
                 return false;
             } else {
@@ -310,6 +351,16 @@ class SystemMediaRoute2Provider extends MediaRoute2Provider {
         mCallback.onSessionUpdated(this, sessionInfo);
     }
 
+    private static class SessionCreationRequest {
+        final long mRequestId;
+        final String mRouteId;
+
+        SessionCreationRequest(long requestId, String routeId) {
+            this.mRequestId = requestId;
+            this.mRouteId = routeId;
+        }
+    }
+
     private class VolumeChangeReceiver extends BroadcastReceiver {
         // This will be called in the main thread.
         @Override