diff --git a/media/bufferpool/2.0/Accessor.cpp b/media/bufferpool/2.0/Accessor.cpp
index b9837f7..3eaea7c 100644
--- a/media/bufferpool/2.0/Accessor.cpp
+++ b/media/bufferpool/2.0/Accessor.cpp
@@ -114,7 +114,10 @@
 }
 
 // Methods from ::android::hardware::media::bufferpool::V2_0::IAccessor follow.
-Return<void> Accessor::connect(connect_cb _hidl_cb) {
+Return<void> Accessor::connect(
+        const sp<::android::hardware::media::bufferpool::V2_0::IObserver>& observer,
+        connect_cb _hidl_cb) {
+    (void)observer;
     sp<Connection> connection;
     ConnectionId connectionId;
     const StatusDescriptor* fmqDesc;
diff --git a/media/bufferpool/2.0/Accessor.h b/media/bufferpool/2.0/Accessor.h
index fa2cb1b..a718da1 100644
--- a/media/bufferpool/2.0/Accessor.h
+++ b/media/bufferpool/2.0/Accessor.h
@@ -18,6 +18,7 @@
 #define ANDROID_HARDWARE_MEDIA_BUFFERPOOL_V2_0_ACCESSOR_H
 
 #include <android/hardware/media/bufferpool/2.0/IAccessor.h>
+#include <android/hardware/media/bufferpool/2.0/IObserver.h>
 #include <bufferpool/BufferPoolTypes.h>
 #include <hidl/MQDescriptor.h>
 #include <hidl/Status.h>
@@ -79,7 +80,7 @@
  */
 struct Accessor : public IAccessor {
     // Methods from ::android::hardware::media::bufferpool::V2_0::IAccessor follow.
-    Return<void> connect(connect_cb _hidl_cb) override;
+    Return<void> connect(const sp<::android::hardware::media::bufferpool::V2_0::IObserver>& observer, connect_cb _hidl_cb) override;
 
     /**
      * Creates a buffer pool accessor which uses the specified allocator.
diff --git a/media/bufferpool/2.0/AccessorImpl.cpp b/media/bufferpool/2.0/AccessorImpl.cpp
index ef62d03..0ba6600 100644
--- a/media/bufferpool/2.0/AccessorImpl.cpp
+++ b/media/bufferpool/2.0/AccessorImpl.cpp
@@ -399,6 +399,9 @@
             case BufferStatus::TRANSFER_ERROR:
                 ret = handleTransferResult(message);
                 break;
+            case BufferStatus::INVALIDATION_ACK:
+                // TODO
+                break;
         }
         if (ret == false) {
             ALOGW("buffer status message processing failure - message : %d connection : %lld",
diff --git a/media/bufferpool/2.0/BufferPoolClient.cpp b/media/bufferpool/2.0/BufferPoolClient.cpp
index 4eeebb4..0f763f7 100644
--- a/media/bufferpool/2.0/BufferPoolClient.cpp
+++ b/media/bufferpool/2.0/BufferPoolClient.cpp
@@ -262,11 +262,13 @@
     : mLocal(false), mValid(false), mAccessor(accessor), mSeqId(0),
       mLastEvictCacheUs(getTimestampNow()) {
     bool valid = false;
+    sp<IObserver> observer; // TODO
     sp<IConnection>& outConnection = mRemoteConnection;
     ConnectionId& id = mConnectionId;
     std::unique_ptr<BufferStatusChannel>& outChannel =
             mReleasing.mStatusChannel;
     Return<void> transResult = accessor->connect(
+            observer,
             [&valid, &outConnection, &id, &outChannel]
             (ResultStatus status, sp<IConnection> connection,
              ConnectionId connectionId, const StatusDescriptor& desc,
diff --git a/media/bufferpool/2.0/BufferPoolClient.h b/media/bufferpool/2.0/BufferPoolClient.h
index 00d6839..1889ea3 100644
--- a/media/bufferpool/2.0/BufferPoolClient.h
+++ b/media/bufferpool/2.0/BufferPoolClient.h
@@ -20,6 +20,7 @@
 #include <memory>
 #include <android/hardware/media/bufferpool/2.0/IAccessor.h>
 #include <android/hardware/media/bufferpool/2.0/IConnection.h>
+#include <android/hardware/media/bufferpool/2.0/IObserver.h>
 #include <bufferpool/BufferPoolTypes.h>
 #include <cutils/native_handle.h>
 #include "Accessor.h"
@@ -33,6 +34,7 @@
 
 using ::android::hardware::media::bufferpool::V2_0::IAccessor;
 using ::android::hardware::media::bufferpool::V2_0::IConnection;
+using ::android::hardware::media::bufferpool::V2_0::IObserver;
 using ::android::hardware::media::bufferpool::V2_0::ResultStatus;
 using ::android::sp;