diff --git a/drm/mediadrm/plugins/mock/MockDrmCryptoPlugin.cpp b/drm/mediadrm/plugins/mock/MockDrmCryptoPlugin.cpp
index c34690b..00f6de3 100644
--- a/drm/mediadrm/plugins/mock/MockDrmCryptoPlugin.cpp
+++ b/drm/mediadrm/plugins/mock/MockDrmCryptoPlugin.cpp
@@ -343,7 +343,31 @@
         Mutex::Autolock lock(mLock);
         ALOGD("MockDrmPlugin::setPropertyString(name=%s, value=%s)",
               name.string(), value.string());
-        mStringProperties.add(name, value);
+
+        if (name == "mock-send-event") {
+            unsigned code, extra;
+            sscanf(value.string(), "%d %d", &code, &extra);
+            DrmPlugin::EventType eventType = (DrmPlugin::EventType)code;
+
+            Vector<uint8_t> const *pSessionId = NULL;
+            ssize_t index = mByteArrayProperties.indexOfKey(String8("mock-event-session-id"));
+            if (index >= 0) {
+                pSessionId = &mByteArrayProperties[index];
+            }
+
+            Vector<uint8_t> const *pData = NULL;
+            index = mByteArrayProperties.indexOfKey(String8("mock-event-data"));
+            if (index >= 0) {
+                pData = &mByteArrayProperties[index];
+            }
+            ALOGD("sending event from mock drm plugin: %d %d %s %s",
+                  (int)code, extra, pSessionId ? vectorToString(*pSessionId) : "{}",
+                  pData ? vectorToString(*pData) : "{}");
+
+            sendEvent(eventType, extra, pSessionId, pData);
+        } else {
+            mStringProperties.add(name, value);
+        }
         return OK;
     }
 
diff --git a/include/media/IDrm.h b/include/media/IDrm.h
index 15d0a75..d630c40 100644
--- a/include/media/IDrm.h
+++ b/include/media/IDrm.h
@@ -17,6 +17,7 @@
 #include <binder/IInterface.h>
 #include <media/stagefright/foundation/ABase.h>
 #include <media/drm/DrmAPI.h>
+#include <media/IDrmClient.h>
 
 #ifndef ANDROID_IDRM_H_
 
@@ -106,6 +107,8 @@
                             Vector<uint8_t> const &signature,
                             bool &match) = 0;
 
+    virtual status_t setListener(const sp<IDrmClient>& listener) = 0;
+
 private:
     DISALLOW_EVIL_CONSTRUCTORS(IDrm);
 };
diff --git a/include/media/IDrmClient.h b/include/media/IDrmClient.h
new file mode 100644
index 0000000..3b2fc7c
--- /dev/null
+++ b/include/media/IDrmClient.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_IDRMCLIENT_H
+#define ANDROID_IDRMCLIENT_H
+
+#include <utils/RefBase.h>
+#include <binder/IInterface.h>
+#include <binder/Parcel.h>
+#include <media/drm/DrmAPI.h>
+
+namespace android {
+
+class IDrmClient: public IInterface
+{
+public:
+    DECLARE_META_INTERFACE(DrmClient);
+
+    virtual void notify(DrmPlugin::EventType eventType, int extra, const Parcel *obj) = 0;
+};
+
+// ----------------------------------------------------------------------------
+
+class BnDrmClient: public BnInterface<IDrmClient>
+{
+public:
+    virtual status_t onTransact(uint32_t code,
+                                const Parcel& data,
+                                Parcel* reply,
+                                uint32_t flags = 0);
+};
+
+}; // namespace android
+
+#endif // ANDROID_IDRMCLIENT_H
diff --git a/media/libmedia/Android.mk b/media/libmedia/Android.mk
index 1ada9c3..fbe71ad 100644
--- a/media/libmedia/Android.mk
+++ b/media/libmedia/Android.mk
@@ -20,6 +20,7 @@
     IAudioRecord.cpp \
     ICrypto.cpp \
     IDrm.cpp \
+    IDrmClient.cpp \
     IHDCP.cpp \
     AudioRecord.cpp \
     AudioSystem.cpp \
diff --git a/media/libmedia/IDrm.cpp b/media/libmedia/IDrm.cpp
index 1641b56..1578846 100644
--- a/media/libmedia/IDrm.cpp
+++ b/media/libmedia/IDrm.cpp
@@ -51,7 +51,8 @@
     ENCRYPT,
     DECRYPT,
     SIGN,
-    VERIFY
+    VERIFY,
+    SET_LISTENER
 };
 
 struct BpDrm : public BpInterface<IDrm> {
@@ -384,6 +385,14 @@
         return reply.readInt32();
     }
 
+    virtual status_t setListener(const sp<IDrmClient>& listener) {
+        Parcel data, reply;
+        data.writeInterfaceToken(IDrm::getInterfaceDescriptor());
+        data.writeStrongBinder(listener->asBinder());
+        remote()->transact(SET_LISTENER, data, &reply);
+        return reply.readInt32();
+    }
+
 private:
     void readVector(Parcel &reply, Vector<uint8_t> &vector) const {
         uint32_t size = reply.readInt32();
@@ -712,6 +721,14 @@
             return OK;
         }
 
+    case SET_LISTENER: {
+        CHECK_INTERFACE(IDrm, data, reply);
+        sp<IDrmClient> listener =
+            interface_cast<IDrmClient>(data.readStrongBinder());
+        reply->writeInt32(setListener(listener));
+        return NO_ERROR;
+    } break;
+
     default:
         return BBinder::onTransact(code, data, reply, flags);
     }
diff --git a/media/libmedia/IDrmClient.cpp b/media/libmedia/IDrmClient.cpp
new file mode 100644
index 0000000..f50715e
--- /dev/null
+++ b/media/libmedia/IDrmClient.cpp
@@ -0,0 +1,81 @@
+/*
+**
+** Copyright 2013, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "IDrmClient"
+#include <utils/Log.h>
+
+#include <utils/RefBase.h>
+#include <binder/IInterface.h>
+#include <binder/Parcel.h>
+
+#include <media/IMediaPlayerClient.h>
+#include <media/IDrmClient.h>
+
+namespace android {
+
+enum {
+    NOTIFY = IBinder::FIRST_CALL_TRANSACTION,
+};
+
+class BpDrmClient: public BpInterface<IDrmClient>
+{
+public:
+    BpDrmClient(const sp<IBinder>& impl)
+        : BpInterface<IDrmClient>(impl)
+    {
+    }
+
+    virtual void notify(DrmPlugin::EventType eventType, int extra, const Parcel *obj)
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IDrmClient::getInterfaceDescriptor());
+        data.writeInt32((int)eventType);
+        data.writeInt32(extra);
+        if (obj && obj->dataSize() > 0) {
+            data.appendFrom(const_cast<Parcel *>(obj), 0, obj->dataSize());
+        }
+        remote()->transact(NOTIFY, data, &reply, IBinder::FLAG_ONEWAY);
+    }
+};
+
+IMPLEMENT_META_INTERFACE(DrmClient, "android.media.IDrmClient");
+
+// ----------------------------------------------------------------------
+
+status_t BnDrmClient::onTransact(
+    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
+{
+    switch (code) {
+        case NOTIFY: {
+            CHECK_INTERFACE(IDrmClient, data, reply);
+            int eventType = data.readInt32();
+            int extra = data.readInt32();
+            Parcel obj;
+            if (data.dataAvail() > 0) {
+                obj.appendFrom(const_cast<Parcel *>(&data), data.dataPosition(), data.dataAvail());
+            }
+
+            notify((DrmPlugin::EventType)eventType, extra, &obj);
+            return NO_ERROR;
+        } break;
+        default:
+            return BBinder::onTransact(code, data, reply, flags);
+    }
+}
+
+}; // namespace android
diff --git a/media/libmediaplayerservice/Drm.cpp b/media/libmediaplayerservice/Drm.cpp
index 5fdb9f4..1e6cd94 100644
--- a/media/libmediaplayerservice/Drm.cpp
+++ b/media/libmediaplayerservice/Drm.cpp
@@ -47,6 +47,7 @@
 
 Drm::Drm()
     : mInitCheck(NO_INIT),
+      mListener(NULL),
       mFactory(NULL),
       mPlugin(NULL) {
 }
@@ -67,6 +68,41 @@
     return mInitCheck;
 }
 
+status_t Drm::setListener(const sp<IDrmClient>& listener)
+{
+    Mutex::Autolock lock(mEventLock);
+    mListener = listener;
+    return NO_ERROR;
+}
+
+void Drm::sendEvent(DrmPlugin::EventType eventType, int extra,
+                    Vector<uint8_t> const *sessionId,
+                    Vector<uint8_t> const *data)
+{
+    mEventLock.lock();
+    sp<IDrmClient> listener = mListener;
+    mEventLock.unlock();
+
+    if (listener != NULL) {
+        Parcel obj;
+        if (sessionId && sessionId->size()) {
+            obj.writeInt32(sessionId->size());
+            obj.write(sessionId->array(), sessionId->size());
+        } else {
+            obj.writeInt32(0);
+        }
+
+        if (data && data->size()) {
+            obj.writeInt32(data->size());
+            obj.write(data->array(), data->size());
+        } else {
+            obj.writeInt32(0);
+        }
+
+        Mutex::Autolock lock(mNotifyLock);
+        listener->notify(eventType, extra, &obj);
+    }
+}
 
 /*
  * Search the plugins directory for a plugin that supports the scheme
@@ -195,7 +231,9 @@
         return mInitCheck;
     }
 
-    return mFactory->createDrmPlugin(uuid, &mPlugin);
+    status_t result = mFactory->createDrmPlugin(uuid, &mPlugin);
+    mPlugin->setListener(this);
+    return result;
 }
 
 status_t Drm::destroyPlugin() {
diff --git a/media/libmediaplayerservice/Drm.h b/media/libmediaplayerservice/Drm.h
index f24921e..3da8ad4 100644
--- a/media/libmediaplayerservice/Drm.h
+++ b/media/libmediaplayerservice/Drm.h
@@ -21,6 +21,7 @@
 #include "SharedLibrary.h"
 
 #include <media/IDrm.h>
+#include <media/IDrmClient.h>
 #include <utils/threads.h>
 
 namespace android {
@@ -28,7 +29,7 @@
 struct DrmFactory;
 struct DrmPlugin;
 
-struct Drm : public BnDrm {
+struct Drm : public BnDrm, public DrmPluginListener {
     Drm();
     virtual ~Drm();
 
@@ -108,10 +109,21 @@
                             Vector<uint8_t> const &signature,
                             bool &match);
 
+    virtual status_t setListener(const sp<IDrmClient>& listener);
+
+    virtual void sendEvent(DrmPlugin::EventType eventType, int extra,
+                           Vector<uint8_t> const *sessionId,
+                           Vector<uint8_t> const *data);
+
 private:
     mutable Mutex mLock;
 
     status_t mInitCheck;
+
+    sp<IDrmClient> mListener;
+    mutable Mutex mEventLock;
+    mutable Mutex mNotifyLock;
+
     sp<SharedLibrary> mLibrary;
     DrmFactory *mFactory;
     DrmPlugin *mPlugin;
diff --git a/media/libstagefright/ACodec.cpp b/media/libstagefright/ACodec.cpp
index c9f8741..ff72b71 100644
--- a/media/libstagefright/ACodec.cpp
+++ b/media/libstagefright/ACodec.cpp
@@ -3416,6 +3416,21 @@
             return true;
         }
 
+        case kWhatResume:
+        {
+            // We'll be active soon enough.
+            return true;
+        }
+
+        case kWhatFlush:
+        {
+            // We haven't even started yet, so we're flushed alright...
+            sp<AMessage> notify = mCodec->mNotify->dup();
+            notify->setInt32("what", ACodec::kWhatFlushCompleted);
+            notify->post();
+            return true;
+        }
+
         default:
             return BaseState::onMessageReceived(msg);
     }
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 9d98f0b..47ca100 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -3122,16 +3122,15 @@
     Vector< sp<Track> > *tracksToRemove
 )
 {
-    sp<Track> trackToRemove;
-
+    size_t count = mActiveTracks.size();
     mixer_state mixerStatus = MIXER_IDLE;
 
     // find out which tracks need to be processed
-    if (mActiveTracks.size() != 0) {
-        sp<Track> t = mActiveTracks[0].promote();
+    for (size_t i = 0; i < count; i++) {
+        sp<Track> t = mActiveTracks[i].promote();
         // The track died recently
         if (t == 0) {
-            return MIXER_IDLE;
+            continue;
         }
 
         Track* const track = t.get();
@@ -3180,35 +3179,40 @@
                 }
                 right = v_clamped/MAX_GAIN;
             }
+            // Only consider last track started for volume and mixer state control.
+            // This is the last entry in mActiveTracks unless a track underruns.
+            // As we only care about the transition phase between two tracks on a
+            // direct output, it is not a problem to ignore the underrun case.
+            if (i == (count - 1)) {
+                if (left != mLeftVolFloat || right != mRightVolFloat) {
+                    mLeftVolFloat = left;
+                    mRightVolFloat = right;
 
-            if (left != mLeftVolFloat || right != mRightVolFloat) {
-                mLeftVolFloat = left;
-                mRightVolFloat = right;
+                    // Convert volumes from float to 8.24
+                    uint32_t vl = (uint32_t)(left * (1 << 24));
+                    uint32_t vr = (uint32_t)(right * (1 << 24));
 
-                // Convert volumes from float to 8.24
-                uint32_t vl = (uint32_t)(left * (1 << 24));
-                uint32_t vr = (uint32_t)(right * (1 << 24));
-
-                // Delegate volume control to effect in track effect chain if needed
-                // only one effect chain can be present on DirectOutputThread, so if
-                // there is one, the track is connected to it
-                if (!mEffectChains.isEmpty()) {
-                    // Do not ramp volume if volume is controlled by effect
-                    mEffectChains[0]->setVolume_l(&vl, &vr);
-                    left = (float)vl / (1 << 24);
-                    right = (float)vr / (1 << 24);
+                    // Delegate volume control to effect in track effect chain if needed
+                    // only one effect chain can be present on DirectOutputThread, so if
+                    // there is one, the track is connected to it
+                    if (!mEffectChains.isEmpty()) {
+                        // Do not ramp volume if volume is controlled by effect
+                        mEffectChains[0]->setVolume_l(&vl, &vr);
+                        left = (float)vl / (1 << 24);
+                        right = (float)vr / (1 << 24);
+                    }
+                    mOutput->stream->set_volume(mOutput->stream, left, right);
                 }
-                mOutput->stream->set_volume(mOutput->stream, left, right);
-            }
 
-            // reset retry count
-            track->mRetryCount = kMaxTrackRetriesDirect;
-            mActiveTrack = t;
-            mixerStatus = MIXER_TRACKS_READY;
+                // reset retry count
+                track->mRetryCount = kMaxTrackRetriesDirect;
+                mActiveTrack = t;
+                mixerStatus = MIXER_TRACKS_READY;
+            }
         } else {
-            // clear effect chain input buffer if an active track underruns to avoid sending
-            // previous audio buffer again to effects
-            if (!mEffectChains.isEmpty()) {
+            // clear effect chain input buffer if the last active track started underruns
+            // to avoid sending previous audio buffer again to effects
+            if (!mEffectChains.isEmpty() && (i == (count -1))) {
                 mEffectChains[0]->clearInputBuffer();
             }
 
@@ -3224,33 +3228,36 @@
                     if (track->isStopped()) {
                         track->reset();
                     }
-                    trackToRemove = track;
+                    tracksToRemove->add(track);
                 }
             } else {
                 // No buffers for this track. Give it a few chances to
                 // fill a buffer, then remove it from active list.
+                // Only consider last track started for mixer state control
                 if (--(track->mRetryCount) <= 0) {
                     ALOGV("BUFFER TIMEOUT: remove(%d) from active list", track->name());
-                    trackToRemove = track;
-                } else {
+                    tracksToRemove->add(track);
+                } else if (i == (count -1)){
                     mixerStatus = MIXER_TRACKS_ENABLED;
                 }
             }
         }
     }
 
-    // FIXME merge this with similar code for removing multiple tracks
     // remove all the tracks that need to be...
-    if (CC_UNLIKELY(trackToRemove != 0)) {
-        tracksToRemove->add(trackToRemove);
-        mActiveTracks.remove(trackToRemove);
-        if (!mEffectChains.isEmpty()) {
-            ALOGV("stopping track on chain %p for session Id: %d", mEffectChains[0].get(),
-                    trackToRemove->sessionId());
-            mEffectChains[0]->decActiveTrackCnt();
-        }
-        if (trackToRemove->isTerminated()) {
-            removeTrack_l(trackToRemove);
+    count = tracksToRemove->size();
+    if (CC_UNLIKELY(count)) {
+        for (size_t i = 0 ; i < count ; i++) {
+            const sp<Track>& track = tracksToRemove->itemAt(i);
+            mActiveTracks.remove(track);
+            if (!mEffectChains.isEmpty()) {
+                ALOGV("stopping track on chain %p for session Id: %d", mEffectChains[0].get(),
+                      track->sessionId());
+                mEffectChains[0]->decActiveTrackCnt();
+            }
+            if (track->isTerminated()) {
+                removeTrack_l(track);
+            }
         }
     }