diff --git a/include/private/surfaceflinger/SharedBufferStack.h b/include/private/surfaceflinger/SharedBufferStack.h
index a1a02e0..0c5a2e4 100644
--- a/include/private/surfaceflinger/SharedBufferStack.h
+++ b/include/private/surfaceflinger/SharedBufferStack.h
@@ -55,12 +55,6 @@
  * 
  */
 
-// When changing these values, the COMPILE_TIME_ASSERT at the end of this
-// file need to be updated.
-const unsigned int NUM_LAYERS_MAX  = 31;
-const unsigned int NUM_BUFFER_MAX  = 16;
-const unsigned int NUM_DISPLAY_MAX = 4;
-
 // ----------------------------------------------------------------------------
 
 class Region;
@@ -82,6 +76,12 @@
     friend class SharedBufferServer;
 
 public:
+    // When changing these values, the COMPILE_TIME_ASSERT at the end of this
+    // file need to be updated.
+    static const unsigned int NUM_LAYERS_MAX  = 31;
+    static const unsigned int NUM_BUFFER_MAX  = 16;
+    static const unsigned int NUM_DISPLAY_MAX = 4;
+
     struct Statistics { // 4 longs
         typedef int32_t usecs_t;
         usecs_t  totalTime;
@@ -147,7 +147,7 @@
     // FIXME: this should be replaced by a lock-less primitive
     Mutex lock;
     Condition cv;
-    SharedBufferStack surfaces[ NUM_LAYERS_MAX ];
+    SharedBufferStack surfaces[ SharedBufferStack::NUM_LAYERS_MAX ];
 };
 
 // ============================================================================
@@ -155,7 +155,7 @@
 class SharedBufferBase
 {
 public:
-    SharedBufferBase(SharedClient* sharedClient, int surface, int num,
+    SharedBufferBase(SharedClient* sharedClient, int surface,
             int32_t identity);
     ~SharedBufferBase();
     uint32_t getIdentity();
@@ -166,9 +166,7 @@
 protected:
     SharedClient* const mSharedClient;
     SharedBufferStack* const mSharedStack;
-    int mNumBuffers;
     const int mIdentity;
-    int32_t computeTail() const;
 
     friend struct Update;
     friend struct QueueUpdate;
@@ -217,8 +215,16 @@
     bool needNewBuffer(int buffer) const;
     status_t setDirtyRegion(int buffer, const Region& reg);
     status_t setCrop(int buffer, const Rect& reg);
-    status_t setBufferCount(int bufferCount);
     
+
+    class SetBufferCountCallback {
+        friend class SharedBufferClient;
+        virtual status_t operator()(int bufferCount) const = 0;
+    protected:
+        virtual ~SetBufferCountCallback() { }
+    };
+    status_t setBufferCount(int bufferCount, const SetBufferCountCallback& ipc);
+
 private:
     friend struct Condition;
     friend struct DequeueCondition;
@@ -249,11 +255,16 @@
         inline const char* name() const { return "LockCondition"; }
     };
 
+    int32_t computeTail() const;
+
+    mutable RWLock mLock;
+    int mNumBuffers;
+
     int32_t tail;
     int32_t undoDequeueTail;
     int32_t queued_head;
     // statistics...
-    nsecs_t mDequeueTime[NUM_BUFFER_MAX];
+    nsecs_t mDequeueTime[SharedBufferStack::NUM_BUFFER_MAX];
 };
 
 // ----------------------------------------------------------------------------
@@ -287,7 +298,8 @@
         size_t mCapacity;
         uint32_t mList;
     public:
-        BufferList(size_t c = NUM_BUFFER_MAX) : mCapacity(c), mList(0) { }
+        BufferList(size_t c = SharedBufferStack::NUM_BUFFER_MAX)
+            : mCapacity(c), mList(0) { }
         status_t add(int value);
         status_t remove(int value);
 
@@ -324,6 +336,9 @@
         }
     };
 
+    // this protects mNumBuffers and mBufferList
+    mutable RWLock mLock;
+    int mNumBuffers;
     BufferList mBufferList;
 
     struct UnlockUpdate : public UpdateBase {
@@ -373,7 +388,7 @@
     uint8_t         connected;
     uint8_t         reserved[3];
     uint32_t        pad[7];
-    display_cblk_t  displays[NUM_DISPLAY_MAX];
+    display_cblk_t  displays[SharedBufferStack::NUM_DISPLAY_MAX];
 };
 
 // ---------------------------------------------------------------------------
diff --git a/libs/surfaceflinger/Barrier.h b/libs/surfaceflinger/Barrier.h
index e2bcf6a..6f8507e 100644
--- a/libs/surfaceflinger/Barrier.h
+++ b/libs/surfaceflinger/Barrier.h
@@ -29,10 +29,6 @@
     inline Barrier() : state(CLOSED) { }
     inline ~Barrier() { }
     void open() {
-        // gcc memory barrier, this makes sure all memory writes
-        // have been issued by gcc. On an SMP system we'd need a real
-        // h/w barrier.
-        asm volatile ("":::"memory");
         Mutex::Autolock _l(lock);
         state = OPENED;
         cv.broadcast();
diff --git a/libs/surfaceflinger/Layer.cpp b/libs/surfaceflinger/Layer.cpp
index 1fe997d..621b7e3 100644
--- a/libs/surfaceflinger/Layer.cpp
+++ b/libs/surfaceflinger/Layer.cpp
@@ -60,7 +60,7 @@
     // no OpenGL operation is possible here, since we might not be
     // in the OpenGL thread.
     lcblk = new SharedBufferServer(
-            client->ctrlblk, i, mBufferManager.getBufferCount(),
+            client->ctrlblk, i, mBufferManager.getDefaultBufferCount(),
             getIdentity());
 
    mBufferManager.setActiveBufferIndex( lcblk->getFrontBuffer() );
@@ -68,7 +68,10 @@
 
 Layer::~Layer()
 {
-    destroy();
+    // FIXME: must be called from the main UI thread
+    EGLDisplay dpy(mFlinger->graphicPlane(0).getEGLDisplay());
+    mBufferManager.destroy(dpy);
+
     // the actual buffers will be destroyed here
     delete lcblk;
 }
@@ -81,17 +84,6 @@
     lcblk->setStatus(NO_INIT);
 }
 
-void Layer::destroy()
-{
-    EGLDisplay dpy(mFlinger->graphicPlane(0).getEGLDisplay());
-    mBufferManager.destroy(dpy);
-
-    mSurface.clear();
-
-    Mutex::Autolock _l(mLock);
-    mWidth = mHeight = 0;
-}
-
 sp<LayerBaseClient::Surface> Layer::createSurface() const
 {
     return mSurface;
@@ -99,9 +91,17 @@
 
 status_t Layer::ditch()
 {
+    // NOTE: Called from the main UI thread
+
     // the layer is not on screen anymore. free as much resources as possible
     mFreezeLock.clear();
-    destroy();
+
+    EGLDisplay dpy(mFlinger->graphicPlane(0).getEGLDisplay());
+    mBufferManager.destroy(dpy);
+    mSurface.clear();
+
+    Mutex::Autolock _l(mLock);
+    mWidth = mHeight = 0;
     return NO_ERROR;
 }
 
@@ -211,7 +211,7 @@
 
 status_t Layer::setBufferCount(int bufferCount)
 {
-    // this ensures our client doesn't go away while we're accessing
+    // Ensures our client doesn't go away while we're accessing
     // the shared area.
     sp<Client> ourClient(client.promote());
     if (ourClient == 0) {
@@ -219,15 +219,10 @@
         return DEAD_OBJECT;
     }
 
-    status_t err;
-
-    // FIXME: resize() below is NOT thread-safe, we need to synchronize
-    // the users of lcblk in our process (ie: retire), and we assume the
-    // client is not mucking with the SharedStack, which is only enforced
-    // by construction, therefore we need to protect ourselves against
-    // buggy and malicious client (as always)
-
-    err = lcblk->resize(bufferCount);
+    // NOTE: lcblk->resize() is protected by an internal lock
+    status_t err = lcblk->resize(bufferCount);
+    if (err == NO_ERROR)
+        mBufferManager.resize(bufferCount);
 
     return err;
 }
@@ -248,7 +243,7 @@
      * This is called from the client's Surface::dequeue(). This can happen
      * at any time, especially while we're in the middle of using the
      * buffer 'index' as our front buffer.
-     * 
+     *
      * Make sure the buffer we're resizing is not the front buffer and has been
      * dequeued. Once this condition is asserted, we are guaranteed that this
      * buffer cannot become the front buffer under our feet, since we're called
@@ -544,12 +539,20 @@
 // ---------------------------------------------------------------------------
 
 Layer::BufferManager::BufferManager(TextureManager& tm)
-    : mTextureManager(tm), mActiveBuffer(0), mFailover(false)
+    : mNumBuffers(NUM_BUFFERS), mTextureManager(tm),
+      mActiveBuffer(0), mFailover(false)
 {
 }
 
-size_t Layer::BufferManager::getBufferCount() const {
-    return NUM_BUFFERS;
+Layer::BufferManager::~BufferManager()
+{
+}
+
+status_t Layer::BufferManager::resize(size_t size)
+{
+    Mutex::Autolock _l(mLock);
+    mNumBuffers = size;
+    return NO_ERROR;
 }
 
 // only for debugging
@@ -568,51 +571,55 @@
 }
 
 Texture Layer::BufferManager::getActiveTexture() const {
-    return mFailover ? mFailoverTexture : mBufferData[mActiveBuffer].texture;
+    Texture res;
+    if (mFailover) {
+        res = mFailoverTexture;
+    } else {
+        static_cast<Image&>(res) = mBufferData[mActiveBuffer].texture;
+    }
+    return res;
 }
 
 sp<GraphicBuffer> Layer::BufferManager::getActiveBuffer() const {
+    const size_t activeBuffer = mActiveBuffer;
+    BufferData const * const buffers = mBufferData;
     Mutex::Autolock _l(mLock);
-    return mBufferData[mActiveBuffer].buffer;
+    return buffers[activeBuffer].buffer;
 }
 
 sp<GraphicBuffer> Layer::BufferManager::detachBuffer(size_t index)
 {
+    BufferData* const buffers = mBufferData;
     sp<GraphicBuffer> buffer;
     Mutex::Autolock _l(mLock);
-    buffer = mBufferData[index].buffer;
-    mBufferData[index].buffer = 0;
+    buffer = buffers[index].buffer;
+    buffers[index].buffer = 0;
     return buffer;
 }
 
 status_t Layer::BufferManager::attachBuffer(size_t index,
         const sp<GraphicBuffer>& buffer)
 {
+    BufferData* const buffers = mBufferData;
     Mutex::Autolock _l(mLock);
-    mBufferData[index].buffer = buffer;
-    mBufferData[index].texture.dirty = true;
-    return NO_ERROR;
-}
-
-status_t Layer::BufferManager::destroyTexture(Texture* tex, EGLDisplay dpy)
-{
-    if (tex->name != -1U) {
-        glDeleteTextures(1, &tex->name);
-        tex->name = -1U;
-    }
-    if (tex->image != EGL_NO_IMAGE_KHR) {
-        eglDestroyImageKHR(dpy, tex->image);
-        tex->image = EGL_NO_IMAGE_KHR;
-    }
+    buffers[index].buffer = buffer;
+    buffers[index].texture.dirty = true;
     return NO_ERROR;
 }
 
 status_t Layer::BufferManager::destroy(EGLDisplay dpy)
 {
-    Mutex::Autolock _l(mLock);
-    for (size_t i=0 ; i<NUM_BUFFERS ; i++) {
-        destroyTexture(&mBufferData[i].texture, dpy);
-        mBufferData[i].buffer = 0;
+    BufferData* const buffers = mBufferData;
+    size_t num;
+    { // scope for the lock
+        Mutex::Autolock _l(mLock);
+        num = mNumBuffers;
+        for (size_t i=0 ; i<num ; i++) {
+            buffers[i].buffer = 0;
+        }
+    }
+    for (size_t i=0 ; i<num ; i++) {
+        destroyTexture(&buffers[i].texture, dpy);
     }
     destroyTexture(&mFailoverTexture, dpy);
     return NO_ERROR;
@@ -622,7 +629,7 @@
         const sp<GraphicBuffer>& buffer)
 {
     size_t index = mActiveBuffer;
-    Texture& texture(mBufferData[index].texture);
+    Image& texture(mBufferData[index].texture);
     status_t err = mTextureManager.initEglImage(&texture, dpy, buffer);
     // if EGLImage fails, we switch to regular texture mode, and we
     // free all resources associated with using EGLImages.
@@ -631,7 +638,8 @@
         destroyTexture(&mFailoverTexture, dpy);
     } else {
         mFailover = true;
-        for (size_t i=0 ; i<NUM_BUFFERS ; i++) {
+        const size_t num = mNumBuffers;
+        for (size_t i=0 ; i<num ; i++) {
             destroyTexture(&mBufferData[i].texture, dpy);
         }
     }
@@ -644,6 +652,19 @@
     return mTextureManager.loadTexture(&mFailoverTexture, dirty, t);
 }
 
+status_t Layer::BufferManager::destroyTexture(Image* tex, EGLDisplay dpy)
+{
+    if (tex->name != -1U) {
+        glDeleteTextures(1, &tex->name);
+        tex->name = -1U;
+    }
+    if (tex->image != EGL_NO_IMAGE_KHR) {
+        eglDestroyImageKHR(dpy, tex->image);
+        tex->image = EGL_NO_IMAGE_KHR;
+    }
+    return NO_ERROR;
+}
+
 // ---------------------------------------------------------------------------
 
 Layer::SurfaceLayer::SurfaceLayer(const sp<SurfaceFlinger>& flinger,
@@ -661,6 +682,11 @@
     sp<GraphicBuffer> buffer;
     sp<Layer> owner(getOwner());
     if (owner != 0) {
+        /*
+         * requestBuffer() cannot be called from the main thread
+         * as it could cause a dead-lock, since it may have to wait
+         * on conditions updated my the main thread.
+         */
         buffer = owner->requestBuffer(index, usage);
     }
     return buffer;
@@ -671,6 +697,11 @@
     status_t err = DEAD_OBJECT;
     sp<Layer> owner(getOwner());
     if (owner != 0) {
+        /*
+         * setBufferCount() cannot be called from the main thread
+         * as it could cause a dead-lock, since it may have to wait
+         * on conditions updated my the main thread.
+         */
         err = owner->setBufferCount(bufferCount);
     }
     return err;
diff --git a/libs/surfaceflinger/Layer.h b/libs/surfaceflinger/Layer.h
index 80fbd6a..247748b 100644
--- a/libs/surfaceflinger/Layer.h
+++ b/libs/surfaceflinger/Layer.h
@@ -90,7 +90,6 @@
 
     sp<GraphicBuffer> requestBuffer(int index, int usage);
     status_t setBufferCount(int bufferCount);
-    void destroy();
 
     class SurfaceLayer : public LayerBaseClient::Surface {
     public:
@@ -120,25 +119,32 @@
                 static const size_t NUM_BUFFERS = 2;
                 struct BufferData {
                     sp<GraphicBuffer>   buffer;
-                    Texture             texture;
+                    Image               texture;
                 };
+                // this lock protect mBufferData[].buffer but since there
+                // is very little contention, we have only one like for
+                // the whole array, we also use it to protect mNumBuffers.
                 mutable Mutex mLock;
-                BufferData          mBufferData[NUM_BUFFERS];
+                BufferData          mBufferData[SharedBufferStack::NUM_BUFFER_MAX];
+                size_t              mNumBuffers;
                 Texture             mFailoverTexture;
                 TextureManager&     mTextureManager;
                 ssize_t             mActiveBuffer;
                 bool                mFailover;
-                static status_t destroyTexture(Texture* tex, EGLDisplay dpy);
+                static status_t destroyTexture(Image* tex, EGLDisplay dpy);
 
             public:
+                static size_t getDefaultBufferCount() { return NUM_BUFFERS; }
                 BufferManager(TextureManager& tm);
-
-                size_t getBufferCount() const;
+                ~BufferManager();
 
                 // detach/attach buffer from/to given index
                 sp<GraphicBuffer> detachBuffer(size_t index);
                 status_t attachBuffer(size_t index, const sp<GraphicBuffer>& buffer);
 
+                // resize the number of active buffers
+                status_t resize(size_t size);
+
                 // ----------------------------------------------
                 // must be called from GL thread
 
@@ -170,6 +176,8 @@
             TextureManager mTextureManager;
             BufferManager mBufferManager;
 
+            // this lock protects mWidth and mHeight which are accessed from
+            // the main thread and requestBuffer's binder transaction thread.
             mutable Mutex mLock;
             uint32_t    mWidth;
             uint32_t    mHeight;
diff --git a/libs/surfaceflinger/LayerBlur.cpp b/libs/surfaceflinger/LayerBlur.cpp
index 2d77876..09c90e8 100644
--- a/libs/surfaceflinger/LayerBlur.cpp
+++ b/libs/surfaceflinger/LayerBlur.cpp
@@ -95,7 +95,9 @@
                     mCacheDirty = false;
                 } else {
                     if (!mAutoRefreshPending) {
-                        mFlinger->signalDelayedEvent(ms2ns(500));
+                        mFlinger->postMessageAsync(
+                                new MessageBase(MessageQueue::INVALIDATE),
+                                ms2ns(500));
                         mAutoRefreshPending = true;
                     }
                 }
diff --git a/libs/surfaceflinger/MessageQueue.cpp b/libs/surfaceflinger/MessageQueue.cpp
index b43d801..d668e88 100644
--- a/libs/surfaceflinger/MessageQueue.cpp
+++ b/libs/surfaceflinger/MessageQueue.cpp
@@ -60,9 +60,9 @@
 {
 }
 
-MessageList::value_type MessageQueue::waitMessage(nsecs_t timeout)
+sp<MessageBase> MessageQueue::waitMessage(nsecs_t timeout)
 {
-    MessageList::value_type result;
+    sp<MessageBase> result;
 
     bool again;
     do {
@@ -132,6 +132,7 @@
         if (again) {
             // the message has been processed. release our reference to it
             // without holding the lock.
+            result->notify();
             result = 0;
         }
         
@@ -141,7 +142,7 @@
 }
 
 status_t MessageQueue::postMessage(
-        const MessageList::value_type& message, nsecs_t relTime, uint32_t flags)
+        const sp<MessageBase>& message, nsecs_t relTime, uint32_t flags)
 {
     return queueMessage(message, relTime, flags);
 }
@@ -154,7 +155,7 @@
 }
 
 status_t MessageQueue::queueMessage(
-        const MessageList::value_type& message, nsecs_t relTime, uint32_t flags)
+        const sp<MessageBase>& message, nsecs_t relTime, uint32_t flags)
 {
     Mutex::Autolock _l(mLock);
     message->when = systemTime() + relTime;
@@ -167,13 +168,13 @@
     return NO_ERROR;
 }
 
-void MessageQueue::dump(const MessageList::value_type& message)
+void MessageQueue::dump(const sp<MessageBase>& message)
 {
     Mutex::Autolock _l(mLock);
     dumpLocked(message);
 }
 
-void MessageQueue::dumpLocked(const MessageList::value_type& message)
+void MessageQueue::dumpLocked(const sp<MessageBase>& message)
 {
     LIST::const_iterator cur(mMessages.begin());
     LIST::const_iterator end(mMessages.end());
diff --git a/libs/surfaceflinger/MessageQueue.h b/libs/surfaceflinger/MessageQueue.h
index dc8138d..890f809 100644
--- a/libs/surfaceflinger/MessageQueue.h
+++ b/libs/surfaceflinger/MessageQueue.h
@@ -25,6 +25,7 @@
 #include <utils/Timers.h>
 #include <utils/List.h>
 
+#include "Barrier.h"
 
 namespace android {
 
@@ -37,7 +38,6 @@
     List< sp<MessageBase> > mList;
     typedef List< sp<MessageBase> > LIST;
 public:
-    typedef sp<MessageBase> value_type;
     inline LIST::iterator begin()                { return mList.begin(); }
     inline LIST::const_iterator begin() const    { return mList.begin(); }
     inline LIST::iterator end()                  { return mList.end(); }
@@ -63,11 +63,19 @@
     
     // return true if message has a handler
     virtual bool handler() { return false; }
+
+    // waits for the handler to be processed
+    void wait() const { barrier.wait(); }
     
+    // releases all waiters. this is done automatically if
+    // handler returns true
+    void notify() const { barrier.open(); }
+
 protected:
     virtual ~MessageBase() { }
 
 private:
+    mutable Barrier barrier;
     friend class LightRefBase<MessageBase>;
 };
 
@@ -82,42 +90,33 @@
     typedef List< sp<MessageBase> > LIST;
 public:
 
-    // this is a work-around the multichar constant warning. A macro would
-    // work too, but would pollute the namespace.
-    template <int a, int b, int c, int d>
-    struct WHAT {
-        static const uint32_t Value = 
-            (uint32_t(a&0xff)<<24)|(uint32_t(b&0xff)<<16)|
-            (uint32_t(c&0xff)<<8)|uint32_t(d&0xff);
-    };
-    
     MessageQueue();
     ~MessageQueue();
 
     // pre-defined messages
     enum {
-        INVALIDATE = WHAT<'_','p','d','t'>::Value
+        INVALIDATE = '_upd'
     };
 
-    MessageList::value_type waitMessage(nsecs_t timeout = -1);
+    sp<MessageBase> waitMessage(nsecs_t timeout = -1);
     
-    status_t postMessage(const MessageList::value_type& message, 
+    status_t postMessage(const sp<MessageBase>& message,
             nsecs_t reltime=0, uint32_t flags = 0);
-        
+
     status_t invalidate();
     
-    void dump(const MessageList::value_type& message);
+    void dump(const sp<MessageBase>& message);
 
 private:
-    status_t queueMessage(const MessageList::value_type& message,
+    status_t queueMessage(const sp<MessageBase>& message,
             nsecs_t reltime, uint32_t flags);
-    void dumpLocked(const MessageList::value_type& message);
+    void dumpLocked(const sp<MessageBase>& message);
     
     Mutex           mLock;
     Condition       mCondition;
     MessageList     mMessages;
     bool            mInvalidate;
-    MessageList::value_type mInvalidateMessage;
+    sp<MessageBase> mInvalidateMessage;
 };
 
 // ---------------------------------------------------------------------------
diff --git a/libs/surfaceflinger/SurfaceFlinger.cpp b/libs/surfaceflinger/SurfaceFlinger.cpp
index 62d829b..5a6893f 100644
--- a/libs/surfaceflinger/SurfaceFlinger.cpp
+++ b/libs/surfaceflinger/SurfaceFlinger.cpp
@@ -426,7 +426,7 @@
             timeout = waitTime>0 ? waitTime : 0;
         }
 
-        MessageList::value_type msg = mEventQueue.waitMessage(timeout);
+        sp<MessageBase> msg = mEventQueue.waitMessage(timeout);
 
         // see if we timed out
         if (isFrozen()) {
@@ -461,9 +461,20 @@
     const_cast<SurfaceFlinger*>(this)->signalEvent();
 }
 
-void SurfaceFlinger::signalDelayedEvent(nsecs_t delay)
+status_t SurfaceFlinger::postMessageAsync(const sp<MessageBase>& msg,
+        nsecs_t reltime, uint32_t flags)
 {
-    mEventQueue.postMessage( new MessageBase(MessageQueue::INVALIDATE), delay);
+    return mEventQueue.postMessage(msg, reltime, flags);
+}
+
+status_t SurfaceFlinger::postMessageSync(const sp<MessageBase>& msg,
+        nsecs_t reltime, uint32_t flags)
+{
+    status_t res = mEventQueue.postMessage(msg, reltime, flags);
+    if (res == NO_ERROR) {
+        msg->wait();
+    }
+    return res;
 }
 
 // ----------------------------------------------------------------------------
@@ -1135,15 +1146,11 @@
     return android_atomic_and(~flags, &mTransactionFlags) & flags;
 }
 
-uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags, nsecs_t delay)
+uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags)
 {
     uint32_t old = android_atomic_or(flags, &mTransactionFlags);
     if ((old & flags)==0) { // wake the server up
-        if (delay > 0) {
-            signalDelayedEvent(delay);
-        } else {
-            signalEvent();
-        }
+        signalEvent();
     }
     return old;
 }
@@ -1245,7 +1252,7 @@
 
     //LOGD("createSurface for pid %d (%d x %d)", pid, w, h);
     int32_t id = client->generateId(pid);
-    if (uint32_t(id) >= NUM_LAYERS_MAX) {
+    if (uint32_t(id) >= SharedBufferStack::NUM_LAYERS_MAX) {
         LOGE("createSurface() failed, generateId = %d", id);
         return surfaceHandle;
     }
@@ -1399,7 +1406,7 @@
         }
     };
 
-    mEventQueue.postMessage( new MessageDestroySurface(this, layer) );
+    postMessageAsync( new MessageDestroySurface(this, layer) );
     return NO_ERROR;
 }
 
@@ -1672,7 +1679,7 @@
 int32_t Client::generateId(int pid)
 {
     const uint32_t i = clz( ~mBitmap );
-    if (i >= NUM_LAYERS_MAX) {
+    if (i >= SharedBufferStack::NUM_LAYERS_MAX) {
         return NO_MEMORY;
     }
     mPid = pid;
@@ -1699,7 +1706,8 @@
 }
 
 bool Client::isValid(int32_t i) const {
-    return (uint32_t(i)<NUM_LAYERS_MAX) && (mBitmap & (1<<(31-i)));
+    return (uint32_t(i)<SharedBufferStack::NUM_LAYERS_MAX) &&
+            (mBitmap & (1<<(31-i)));
 }
 
 sp<LayerBaseClient> Client::getLayerUser(int32_t i) const {
diff --git a/libs/surfaceflinger/SurfaceFlinger.h b/libs/surfaceflinger/SurfaceFlinger.h
index 9c8de51..2558324 100644
--- a/libs/surfaceflinger/SurfaceFlinger.h
+++ b/libs/surfaceflinger/SurfaceFlinger.h
@@ -255,8 +255,6 @@
 public:     // hack to work around gcc 4.0.3 bug
             void        signalEvent();
 private:
-            void        signalDelayedEvent(nsecs_t delay);
-
             void        handleConsoleEvents();
             void        handleTransaction(uint32_t transactionFlags);
             void        handleTransactionLocked(
@@ -286,7 +284,7 @@
             void        free_resources_l();
 
             uint32_t    getTransactionFlags(uint32_t flags);
-            uint32_t    setTransactionFlags(uint32_t flags, nsecs_t delay = 0);
+            uint32_t    setTransactionFlags(uint32_t flags);
             void        commitTransaction();
 
 
@@ -310,7 +308,12 @@
            
 
     mutable     MessageQueue    mEventQueue;
-    
+
+    status_t postMessageAsync(const sp<MessageBase>& msg,
+            nsecs_t reltime=0, uint32_t flags = 0);
+
+    status_t postMessageSync(const sp<MessageBase>& msg,
+            nsecs_t reltime=0, uint32_t flags = 0);
                 
                 
                 // access must be protected by mStateLock
diff --git a/libs/surfaceflinger/TextureManager.cpp b/libs/surfaceflinger/TextureManager.cpp
index e5d5302..ee2159b 100644
--- a/libs/surfaceflinger/TextureManager.cpp
+++ b/libs/surfaceflinger/TextureManager.cpp
@@ -68,7 +68,7 @@
     return false;
 }
 
-status_t TextureManager::initEglImage(Texture* texture,
+status_t TextureManager::initEglImage(Image* texture,
         EGLDisplay dpy, const sp<GraphicBuffer>& buffer)
 {
     status_t err = NO_ERROR;
@@ -108,7 +108,6 @@
             err = INVALID_OPERATION;
         } else {
             // Everything went okay!
-            texture->NPOTAdjust = false;
             texture->dirty  = false;
             texture->width  = clientBuf->width;
             texture->height = clientBuf->height;
diff --git a/libs/surfaceflinger/TextureManager.h b/libs/surfaceflinger/TextureManager.h
index 90cb62b..d0acfe9 100644
--- a/libs/surfaceflinger/TextureManager.h
+++ b/libs/surfaceflinger/TextureManager.h
@@ -36,21 +36,24 @@
 
 // ---------------------------------------------------------------------------
 
-struct Texture {
-    Texture() : name(-1U), width(0), height(0),
-        image(EGL_NO_IMAGE_KHR), transform(0),
-        NPOTAdjust(false), dirty(true) { }
+struct Image {
+    Image() : name(-1U), image(EGL_NO_IMAGE_KHR), width(0), height(0),
+        transform(0), dirty(true) { }
     GLuint        name;
+    EGLImageKHR   image;
     GLuint        width;
     GLuint        height;
+    uint32_t      transform;
+    bool          dirty;
+};
+
+struct Texture : public Image {
+    Texture() : Image(), NPOTAdjust(false)  { }
     GLuint        potWidth;
     GLuint        potHeight;
     GLfloat       wScale;
     GLfloat       hScale;
-    EGLImageKHR   image;
-    uint32_t      transform;
     bool          NPOTAdjust;
-    bool          dirty;
 };
 
 // ---------------------------------------------------------------------------
@@ -68,7 +71,7 @@
             const Region& dirty, const GGLSurface& t);
 
     // make active buffer an EGLImage if needed
-    status_t initEglImage(Texture* texture,
+    status_t initEglImage(Image* texture,
             EGLDisplay dpy, const sp<GraphicBuffer>& buffer);
 };
 
diff --git a/libs/surfaceflinger_client/SharedBufferStack.cpp b/libs/surfaceflinger_client/SharedBufferStack.cpp
index dab8ed8..5deeabb 100644
--- a/libs/surfaceflinger_client/SharedBufferStack.cpp
+++ b/libs/surfaceflinger_client/SharedBufferStack.cpp
@@ -44,7 +44,7 @@
 
 // these functions are used by the clients
 status_t SharedClient::validate(size_t i) const {
-    if (uint32_t(i) >= uint32_t(NUM_LAYERS_MAX))
+    if (uint32_t(i) >= uint32_t(SharedBufferStack::NUM_LAYERS_MAX))
         return BAD_INDEX;
     return surfaces[i].status;
 }
@@ -144,10 +144,10 @@
 // ----------------------------------------------------------------------------
 
 SharedBufferBase::SharedBufferBase(SharedClient* sharedClient,
-        int surface, int num, int32_t identity)
+        int surface, int32_t identity)
     : mSharedClient(sharedClient), 
       mSharedStack(sharedClient->surfaces + surface),
-      mNumBuffers(num), mIdentity(identity)
+      mIdentity(identity)
 {
 }
 
@@ -179,34 +179,16 @@
     char buffer[SIZE];
     String8 result;
     SharedBufferStack& stack( *mSharedStack );
-    int tail = computeTail();
     snprintf(buffer, SIZE, 
-            "%s[ head=%2d, available=%2d, queued=%2d, tail=%2d ] "
+            "%s[ head=%2d, available=%2d, queued=%2d ] "
             "reallocMask=%08x, inUse=%2d, identity=%d, status=%d",
-            prefix, stack.head, stack.available, stack.queued, tail,
+            prefix, stack.head, stack.available, stack.queued,
             stack.reallocMask, stack.inUse, stack.identity, stack.status);
     result.append(buffer);
-
-    snprintf(buffer, SIZE, " { ");
-    result.append(buffer);
-
-    for (int i=0 ; i<mNumBuffers ; i++) {
-        snprintf(buffer, SIZE, "%d ", stack.index[i]);
-        result.append(buffer);
-    }
-
-    snprintf(buffer, SIZE, " }\n");
-    result.append(buffer);
-
+    result.append("\n");
     return result;
 }
 
-int32_t SharedBufferBase::computeTail() const
-{
-    SharedBufferStack& stack( *mSharedStack );
-    return (mNumBuffers + stack.head - stack.available + 1) % mNumBuffers;
-}
-
 status_t SharedBufferBase::waitForCondition(const ConditionBase& condition)
 {
     const SharedBufferStack& stack( *mSharedStack );
@@ -270,7 +252,7 @@
 }
 bool SharedBufferServer::ReallocateCondition::operator()() const {
     int32_t head = stack.head;
-    if (uint32_t(head) >= NUM_BUFFER_MAX) {
+    if (uint32_t(head) >= SharedBufferStack::NUM_BUFFER_MAX) {
         // if stack.head is messed up, we cannot allow the server to
         // crash (since stack.head is mapped on the client side)
         stack.status = BAD_VALUE;
@@ -318,7 +300,7 @@
 }
 ssize_t SharedBufferServer::RetireUpdate::operator()() {
     int32_t head = stack.head;
-    if (uint32_t(head) >= NUM_BUFFER_MAX)
+    if (uint32_t(head) >= SharedBufferStack::NUM_BUFFER_MAX)
         return BAD_VALUE;
 
     // Preventively lock the current buffer before updating queued.
@@ -361,14 +343,20 @@
 
 SharedBufferClient::SharedBufferClient(SharedClient* sharedClient,
         int surface, int num, int32_t identity)
-    : SharedBufferBase(sharedClient, surface, num, identity),
-      tail(0), undoDequeueTail(0)
+    : SharedBufferBase(sharedClient, surface, identity),
+      mNumBuffers(num), tail(0), undoDequeueTail(0)
 {
     SharedBufferStack& stack( *mSharedStack );
     tail = computeTail();
     queued_head = stack.head;
 }
 
+int32_t SharedBufferClient::computeTail() const
+{
+    SharedBufferStack& stack( *mSharedStack );
+    return (mNumBuffers + stack.head - stack.available + 1) % mNumBuffers;
+}
+
 ssize_t SharedBufferClient::dequeue()
 {
     SharedBufferStack& stack( *mSharedStack );
@@ -377,7 +365,9 @@
         LOGW("dequeue: tail=%d, head=%d, avail=%d, queued=%d",
                 tail, stack.head, stack.available, stack.queued);
     }
-        
+
+    RWLock::AutoRLock _rd(mLock);
+
     const nsecs_t dequeueTime = systemTime(SYSTEM_TIME_THREAD);
 
     //LOGD("[%d] about to dequeue a buffer",
@@ -407,6 +397,8 @@
 
 status_t SharedBufferClient::undoDequeue(int buf)
 {
+    RWLock::AutoRLock _rd(mLock);
+
     // TODO: we can only undo the previous dequeue, we should
     // enforce that in the api
     UndoDequeueUpdate update(this);
@@ -419,6 +411,8 @@
 
 status_t SharedBufferClient::lock(int buf)
 {
+    RWLock::AutoRLock _rd(mLock);
+
     SharedBufferStack& stack( *mSharedStack );
     LockCondition condition(this, buf);
     status_t err = waitForCondition(condition);
@@ -427,6 +421,8 @@
 
 status_t SharedBufferClient::queue(int buf)
 {
+    RWLock::AutoRLock _rd(mLock);
+
     SharedBufferStack& stack( *mSharedStack );
 
     queued_head = (queued_head + 1) % mNumBuffers;
@@ -460,21 +456,29 @@
     return stack.setDirtyRegion(buf, reg);
 }
 
-status_t SharedBufferClient::setBufferCount(int bufferCount)
+status_t SharedBufferClient::setBufferCount(
+        int bufferCount, const SetBufferCountCallback& ipc)
 {
     SharedBufferStack& stack( *mSharedStack );
-    if (uint32_t(bufferCount) >= NUM_BUFFER_MAX)
+    if (uint32_t(bufferCount) >= SharedBufferStack::NUM_BUFFER_MAX)
         return BAD_VALUE;
-    mNumBuffers = bufferCount;
-    queued_head = (stack.head + stack.queued) % mNumBuffers;
-    return NO_ERROR;
+
+    RWLock::AutoWLock _wr(mLock);
+
+    status_t err = ipc(bufferCount);
+    if (err == NO_ERROR) {
+        mNumBuffers = bufferCount;
+        queued_head = (stack.head + stack.queued) % mNumBuffers;
+    }
+    return err;
 }
 
 // ----------------------------------------------------------------------------
 
 SharedBufferServer::SharedBufferServer(SharedClient* sharedClient,
         int surface, int num, int32_t identity)
-    : SharedBufferBase(sharedClient, surface, num, identity)
+    : SharedBufferBase(sharedClient, surface, identity),
+      mNumBuffers(num)
 {
     mSharedStack->init(identity);
     mSharedStack->head = num-1;
@@ -490,10 +494,12 @@
 
 ssize_t SharedBufferServer::retireAndLock()
 {
+    RWLock::AutoRLock _l(mLock);
+
     RetireUpdate update(this, mNumBuffers);
     ssize_t buf = updateCondition( update );
     if (buf >= 0) {
-        if (uint32_t(buf) >= NUM_BUFFER_MAX)
+        if (uint32_t(buf) >= SharedBufferStack::NUM_BUFFER_MAX)
             return BAD_VALUE;
         SharedBufferStack& stack( *mSharedStack );
         buf = stack.index[buf];
@@ -520,6 +526,8 @@
 
 status_t SharedBufferServer::reallocate()
 {
+    RWLock::AutoRLock _l(mLock);
+
     SharedBufferStack& stack( *mSharedStack );
     uint32_t mask = (1<<mNumBuffers)-1;
     android_atomic_or(mask, &stack.reallocMask); 
@@ -534,6 +542,13 @@
 
 status_t SharedBufferServer::assertReallocate(int buf)
 {
+    /*
+     * NOTE: it's safe to hold mLock for read while waiting for
+     * the ReallocateCondition because that condition is not updated
+     * by the thread that holds mLock for write.
+     */
+    RWLock::AutoRLock _l(mLock);
+
     // TODO: need to validate "buf"
     ReallocateCondition condition(this, buf);
     status_t err = waitForCondition(condition);
@@ -546,9 +561,7 @@
     return stack.getDirtyRegion(buf);
 }
 
-
 /*
- *
  * NOTE: this is not thread-safe on the server-side, meaning
  * 'head' cannot move during this operation. The client-side
  * can safely operate an usual.
@@ -556,9 +569,11 @@
  */
 status_t SharedBufferServer::resize(int newNumBuffers)
 {
-    if (uint32_t(newNumBuffers) >= NUM_BUFFER_MAX)
+    if (uint32_t(newNumBuffers) >= SharedBufferStack::NUM_BUFFER_MAX)
         return BAD_VALUE;
 
+    RWLock::AutoWLock _l(mLock);
+
     // for now we're not supporting shrinking
     const int numBuffers = mNumBuffers;
     if (newNumBuffers < numBuffers)
@@ -569,7 +584,7 @@
 
     // read the head, make sure it's valid
     int32_t head = stack.head;
-    if (uint32_t(head) >= NUM_BUFFER_MAX)
+    if (uint32_t(head) >= SharedBufferStack::NUM_BUFFER_MAX)
         return BAD_VALUE;
 
     int base = numBuffers;
diff --git a/libs/surfaceflinger_client/Surface.cpp b/libs/surfaceflinger_client/Surface.cpp
index afbeafb..4d5c0b6 100644
--- a/libs/surfaceflinger_client/Surface.cpp
+++ b/libs/surfaceflinger_client/Surface.cpp
@@ -678,19 +678,18 @@
     sp<ISurface> s(mSurface);
     if (s == 0) return NO_INIT;
 
-    // FIXME: this needs to be synchronized dequeue/queue
+    class SetBufferCountIPC : public SharedBufferClient::SetBufferCountCallback {
+        sp<ISurface> surface;
+        virtual status_t operator()(int bufferCount) const {
+            return surface->setBufferCount(bufferCount);
+        }
+    public:
+        SetBufferCountIPC(const sp<ISurface>& surface) : surface(surface) { }
+    } ipc(s);
 
-    status_t err = s->setBufferCount(bufferCount);
+    status_t err = mSharedBufferClient->setBufferCount(bufferCount, ipc);
     LOGE_IF(err, "ISurface::setBufferCount(%d) returned %s",
             bufferCount, strerror(-err));
-    if (err == NO_ERROR) {
-        err = mSharedBufferClient->getStatus();
-        LOGE_IF(err,  "Surface (identity=%d) state = %d", mIdentity, err);
-        if (!err) {
-            // update our local copy of the buffer count
-            mSharedBufferClient->setBufferCount(bufferCount);
-        }
-    }
     return err;
 }
 
diff --git a/libs/surfaceflinger_client/SurfaceComposerClient.cpp b/libs/surfaceflinger_client/SurfaceComposerClient.cpp
index 85167da..9ac73d2 100644
--- a/libs/surfaceflinger_client/SurfaceComposerClient.cpp
+++ b/libs/surfaceflinger_client/SurfaceComposerClient.cpp
@@ -250,7 +250,7 @@
 status_t SurfaceComposerClient::getDisplayInfo(
         DisplayID dpy, DisplayInfo* info)
 {
-    if (uint32_t(dpy)>=NUM_DISPLAY_MAX)
+    if (uint32_t(dpy)>=SharedBufferStack::NUM_DISPLAY_MAX)
         return BAD_VALUE;
 
     volatile surface_flinger_cblk_t const * cblk = get_cblk();
@@ -268,7 +268,7 @@
 
 ssize_t SurfaceComposerClient::getDisplayWidth(DisplayID dpy)
 {
-    if (uint32_t(dpy)>=NUM_DISPLAY_MAX)
+    if (uint32_t(dpy)>=SharedBufferStack::NUM_DISPLAY_MAX)
         return BAD_VALUE;
     volatile surface_flinger_cblk_t const * cblk = get_cblk();
     volatile display_cblk_t const * dcblk = cblk->displays + dpy;
@@ -277,7 +277,7 @@
 
 ssize_t SurfaceComposerClient::getDisplayHeight(DisplayID dpy)
 {
-    if (uint32_t(dpy)>=NUM_DISPLAY_MAX)
+    if (uint32_t(dpy)>=SharedBufferStack::NUM_DISPLAY_MAX)
         return BAD_VALUE;
     volatile surface_flinger_cblk_t const * cblk = get_cblk();
     volatile display_cblk_t const * dcblk = cblk->displays + dpy;
@@ -286,7 +286,7 @@
 
 ssize_t SurfaceComposerClient::getDisplayOrientation(DisplayID dpy)
 {
-    if (uint32_t(dpy)>=NUM_DISPLAY_MAX)
+    if (uint32_t(dpy)>=SharedBufferStack::NUM_DISPLAY_MAX)
         return BAD_VALUE;
     volatile surface_flinger_cblk_t const * cblk = get_cblk();
     volatile display_cblk_t const * dcblk = cblk->displays + dpy;
@@ -345,7 +345,7 @@
         sp<ISurface> surface = mClient->createSurface(&data, pid, name,
                 display, w, h, format, flags);
         if (surface != 0) {
-            if (uint32_t(data.token) < NUM_LAYERS_MAX) {
+            if (uint32_t(data.token) < SharedBufferStack::NUM_LAYERS_MAX) {
                 result = new SurfaceControl(this, surface, data, w, h, format, flags);
             }
         }
diff --git a/libs/surfaceflinger_client/tests/SharedBufferStack/SharedBufferStackTest.cpp b/libs/surfaceflinger_client/tests/SharedBufferStack/SharedBufferStackTest.cpp
index f490a65..f409f48 100644
--- a/libs/surfaceflinger_client/tests/SharedBufferStack/SharedBufferStackTest.cpp
+++ b/libs/surfaceflinger_client/tests/SharedBufferStack/SharedBufferStackTest.cpp
@@ -54,8 +54,16 @@
 
 
     printf("resize test\n");
-    s.resize(6);
-    c.setBufferCount(6);
+    class SetBufferCountIPC : public SharedBufferClient::SetBufferCountCallback {
+        SharedBufferServer& s;
+        virtual status_t operator()(int bufferCount) const {
+            return s.resize(bufferCount);
+        }
+    public:
+        SetBufferCountIPC(SharedBufferServer& s) : s(s) { }
+    } resize(s);
+
+    c.setBufferCount(6, resize);
     int list3[6] = {3, 2, 1, 4, 5, 0};
     test0(s, c, 6, list3);