diff --git a/libs/surfaceflinger/LayerBase.cpp b/libs/surfaceflinger/LayerBase.cpp
index 51673ff..090404e 100644
--- a/libs/surfaceflinger/LayerBase.cpp
+++ b/libs/surfaceflinger/LayerBase.cpp
@@ -500,7 +500,7 @@
 
 // ---------------------------------------------------------------------------
 
-int32_t LayerBaseClient::sIdentity = 0;
+int32_t LayerBaseClient::sIdentity = 1;
 
 LayerBaseClient::LayerBaseClient(SurfaceFlinger* flinger, DisplayID display,
         const sp<Client>& client, int32_t i)
diff --git a/libs/surfaceflinger_client/SharedBufferStack.cpp b/libs/surfaceflinger_client/SharedBufferStack.cpp
index b452259..2577dc0 100644
--- a/libs/surfaceflinger_client/SharedBufferStack.cpp
+++ b/libs/surfaceflinger_client/SharedBufferStack.cpp
@@ -155,12 +155,6 @@
 {
 }
 
-uint32_t SharedBufferBase::getIdentity()
-{
-    SharedBufferStack& stack( *mSharedStack );
-    return stack.identity;
-}
-
 status_t SharedBufferBase::getStatus() const
 {
     SharedBufferStack& stack( *mSharedStack );
diff --git a/libs/surfaceflinger_client/Surface.cpp b/libs/surfaceflinger_client/Surface.cpp
index 71504fa..534a54e 100644
--- a/libs/surfaceflinger_client/Surface.cpp
+++ b/libs/surfaceflinger_client/Surface.cpp
@@ -151,75 +151,75 @@
 }
 
 status_t SurfaceControl::setLayer(int32_t layer) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setLayer(mToken, layer);
 }
 status_t SurfaceControl::setPosition(int32_t x, int32_t y) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setPosition(mToken, x, y);
 }
 status_t SurfaceControl::setSize(uint32_t w, uint32_t h) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setSize(mToken, w, h);
 }
 status_t SurfaceControl::hide() {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->hide(mToken);
 }
 status_t SurfaceControl::show(int32_t layer) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->show(mToken, layer);
 }
 status_t SurfaceControl::freeze() {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->freeze(mToken);
 }
 status_t SurfaceControl::unfreeze() {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->unfreeze(mToken);
 }
 status_t SurfaceControl::setFlags(uint32_t flags, uint32_t mask) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setFlags(mToken, flags, mask);
 }
 status_t SurfaceControl::setTransparentRegionHint(const Region& transparent) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setTransparentRegionHint(mToken, transparent);
 }
 status_t SurfaceControl::setAlpha(float alpha) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setAlpha(mToken, alpha);
 }
 status_t SurfaceControl::setMatrix(float dsdx, float dtdx, float dsdy, float dtdy) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setMatrix(mToken, dsdx, dtdx, dsdy, dtdy);
 }
 status_t SurfaceControl::setFreezeTint(uint32_t tint) {
-    const sp<SurfaceComposerClient>& client(mClient);
     status_t err = validate();
     if (err < 0) return err;
+    const sp<SurfaceComposerClient>& client(mClient);
     return client->setFreezeTint(mToken, tint);
 }
 
@@ -230,23 +230,6 @@
                 mToken, mIdentity, mClient.get());
         return NO_INIT;
     }
-    SharedClient const* cblk = mClient->mControl;
-    if (cblk == 0) {
-        LOGE("cblk is null (surface id=%d, identity=%u)", mToken, mIdentity);
-        return NO_INIT;
-    }
-    status_t err = cblk->validate(mToken);
-    if (err != NO_ERROR) {
-        LOGE("surface (id=%d, identity=%u) is invalid, err=%d (%s)",
-                mToken, mIdentity, err, strerror(-err));
-        return err;
-    }
-    uint32_t identity = cblk->getIdentity(mToken);
-    if (mIdentity != identity) {
-        LOGE("using an invalid surface id=%d, identity=%u should be %d",
-                mToken, mIdentity, identity);
-        return NO_INIT;
-    }
     return NO_ERROR;
 }
 
@@ -300,16 +283,15 @@
       mToken(surface->mToken), mIdentity(surface->mIdentity),
       mFormat(surface->mFormat), mFlags(surface->mFlags),
       mBufferMapper(GraphicBufferMapper::get()), mSharedBufferClient(NULL),
+      mInitCheck(NO_INIT),
       mWidth(surface->mWidth), mHeight(surface->mHeight)
 {
-    mSharedBufferClient = new SharedBufferClient(
-            mClient->mControl, mToken, 2, mIdentity);
-
     init();
 }
 
 Surface::Surface(const Parcel& parcel)
-    :  mBufferMapper(GraphicBufferMapper::get()), mSharedBufferClient(NULL)
+    :  mBufferMapper(GraphicBufferMapper::get()),
+       mSharedBufferClient(NULL), mInitCheck(NO_INIT)
 {
     sp<IBinder> clientBinder = parcel.readStrongBinder();
     mSurface    = interface_cast<ISurface>(parcel.readStrongBinder());
@@ -323,9 +305,6 @@
     // FIXME: what does that mean if clientBinder is NULL here?
     if (clientBinder != NULL) {
         mClient = SurfaceComposerClient::clientForConnection(clientBinder);
-
-        mSharedBufferClient = new SharedBufferClient(
-                mClient->mControl, mToken, 2, mIdentity);
     }
 
     init();
@@ -339,7 +318,7 @@
     android_native_window_t::queueBuffer      = queueBuffer;
     android_native_window_t::query            = query;
     android_native_window_t::perform          = perform;
-    mSwapRectangle.makeInvalid();
+
     DisplayInfo dinfo;
     SurfaceComposerClient::getDisplayInfo(0, &dinfo);
     const_cast<float&>(android_native_window_t::xdpi) = dinfo.xdpi;
@@ -348,11 +327,19 @@
     const_cast<int&>(android_native_window_t::minSwapInterval) = 1;
     const_cast<int&>(android_native_window_t::maxSwapInterval) = 1;
     const_cast<uint32_t&>(android_native_window_t::flags) = 0;
-    // be default we request a hardware surface
+
     mConnected = 0;
+    mSwapRectangle.makeInvalid();
     // two buffers by default
     mBuffers.setCapacity(2);
     mBuffers.insertAt(0, 2);
+
+    if (mClient != 0) {
+        mSharedBufferClient = new SharedBufferClient(
+                mClient->getSharedClient(), mToken, 2, mIdentity);
+    }
+
+    mInitCheck = initCheck();
 }
 
 Surface::~Surface()
@@ -375,56 +362,73 @@
     IPCThreadState::self()->flushCommands();
 }
 
-sp<SurfaceComposerClient> Surface::getClient() const {
-    return mClient;
-}
-
-sp<ISurface> Surface::getISurface() const {
-    return mSurface;
-}
-
-bool Surface::isValid() {
-    return mToken>=0 && mClient!=0;
-}
-
-status_t Surface::validate() const
+status_t Surface::initCheck() const
 {
-    sp<SurfaceComposerClient> client(getClient());
     if (mToken<0 || mClient==0) {
-        LOGE("invalid token (%d, identity=%u) or client (%p)", 
-                mToken, mIdentity, client.get());
         return NO_INIT;
     }
-    SharedClient const* cblk = mClient->mControl;
+    SharedClient const* cblk = mClient->getSharedClient();
     if (cblk == 0) {
         LOGE("cblk is null (surface id=%d, identity=%u)", mToken, mIdentity);
         return NO_INIT;
     }
+    return NO_ERROR;
+}
+
+bool Surface::isValid() {
+    return mInitCheck == NO_ERROR;
+}
+
+status_t Surface::validate() const
+{
+    // check that we initialized ourself properly
+    if (mInitCheck != NO_ERROR) {
+        LOGE("invalid token (%d, identity=%u) or client (%p)",
+                mToken, mIdentity, mClient.get());
+        return mInitCheck;
+    }
+
+    // verify the identity of this surface
+    SharedClient const* cblk = mClient->getSharedClient();
+
+    uint32_t identity = cblk->getIdentity(mToken);
+
+    // this is a bit of a (temporary) special case, identity==0 means that
+    // no operation are allowed from the client (eg: dequeue/queue), this
+    // is used with PUSH_BUFFER surfaces for instance
+    if (identity == 0) {
+        LOGE("[Surface] invalid operation (identity=%u)", mIdentity);
+        return INVALID_OPERATION;
+    }
+
+    if (mIdentity != identity) {
+        LOGE("[Surface] using an invalid surface id=%d, "
+                "identity=%u should be %d",
+                mToken, mIdentity, identity);
+        return NO_INIT;
+    }
+
+    // check the surface didn't become invalid
     status_t err = cblk->validate(mToken);
     if (err != NO_ERROR) {
         LOGE("surface (id=%d, identity=%u) is invalid, err=%d (%s)",
                 mToken, mIdentity, err, strerror(-err));
         return err;
     }
-    uint32_t identity = cblk->getIdentity(mToken);
-    if (mIdentity != identity) {
-        LOGE("using an invalid surface id=%d, identity=%u should be %d",
-                mToken, mIdentity, identity);
-        return NO_INIT;
-    }
+
     return NO_ERROR;
 }
 
-
-bool Surface::isSameSurface(
-        const sp<Surface>& lhs, const sp<Surface>& rhs) 
-{
+bool Surface::isSameSurface(const sp<Surface>& lhs, const sp<Surface>& rhs) {
     if (lhs == 0 || rhs == 0)
         return false;
-
     return lhs->mSurface->asBinder() == rhs->mSurface->asBinder();
 }
 
+sp<ISurface> Surface::getISurface() const {
+    return mSurface;
+}
+
 // ----------------------------------------------------------------------------
 
 int Surface::setSwapInterval(android_native_window_t* window, int interval) {
@@ -485,7 +489,6 @@
 
 int Surface::dequeueBuffer(android_native_buffer_t** buffer)
 {
-    sp<SurfaceComposerClient> client(getClient());
     status_t err = validate();
     if (err != NO_ERROR)
         return err;
@@ -534,7 +537,6 @@
 
 int Surface::lockBuffer(android_native_buffer_t* buffer)
 {
-    sp<SurfaceComposerClient> client(getClient());
     status_t err = validate();
     if (err != NO_ERROR)
         return err;
@@ -547,7 +549,6 @@
 
 int Surface::queueBuffer(android_native_buffer_t* buffer)
 {   
-    sp<SurfaceComposerClient> client(getClient());
     status_t err = validate();
     if (err != NO_ERROR)
         return err;
@@ -564,6 +565,7 @@
 
     if (err == NO_ERROR) {
         // FIXME: can we avoid this IPC if we know there is one pending?
+        const sp<SurfaceComposerClient>& client(mClient);
         client->signalServer();
     }
     return err;
diff --git a/libs/surfaceflinger_client/SurfaceComposerClient.cpp b/libs/surfaceflinger_client/SurfaceComposerClient.cpp
index 9ac73d2..96ed566 100644
--- a/libs/surfaceflinger_client/SurfaceComposerClient.cpp
+++ b/libs/surfaceflinger_client/SurfaceComposerClient.cpp
@@ -123,11 +123,11 @@
 {
     sp<ISurfaceComposer> sm(getComposerService());
     if (sm == 0) {
-        _init(0, 0);
+        init(0, 0);
         return;
     }
 
-    _init(sm, sm->createConnection());
+    init(sm, sm->createConnection());
 
     if (mClient != 0) {
         Mutex::Autolock _l(gLock);
@@ -139,9 +139,14 @@
 SurfaceComposerClient::SurfaceComposerClient(
         const sp<ISurfaceComposer>& sm, const sp<IBinder>& conn)
 {
-    _init(sm, interface_cast<ISurfaceFlingerClient>(conn));
+    init(sm, interface_cast<ISurfaceFlingerClient>(conn));
 }
 
+SurfaceComposerClient::~SurfaceComposerClient()
+{
+    VERBOSE("Destroying client %p, conn %p", this, mClient.get());
+    dispose();
+}
 
 status_t SurfaceComposerClient::linkToComposerDeath(
         const sp<IBinder::DeathRecipient>& recipient,
@@ -151,7 +156,7 @@
     return sm->asBinder()->linkToDeath(recipient, cookie, flags);    
 }
 
-void SurfaceComposerClient::_init(
+void SurfaceComposerClient::init(
         const sp<ISurfaceComposer>& sm, const sp<ISurfaceFlingerClient>& conn)
 {
     VERBOSE("Creating client %p, conn %p", this, conn.get());
@@ -172,10 +177,9 @@
     mControl = static_cast<SharedClient *>(mControlMemory->getBase());
 }
 
-SurfaceComposerClient::~SurfaceComposerClient()
+SharedClient* SurfaceComposerClient::getSharedClient() const
 {
-    VERBOSE("Destroying client %p, conn %p", this, mClient.get());
-    dispose();
+    return mControl;
 }
 
 status_t SurfaceComposerClient::initCheck() const
@@ -488,7 +492,7 @@
     return NO_ERROR;
 }
 
-layer_state_t* SurfaceComposerClient::_get_state_l(SurfaceID index)
+layer_state_t* SurfaceComposerClient::get_state_l(SurfaceID index)
 {
     // API usage error, do nothing.
     if (mTransactionOpen<=0) {
@@ -508,49 +512,49 @@
     return mStates.editArray() + i;
 }
 
-layer_state_t* SurfaceComposerClient::_lockLayerState(SurfaceID id)
+layer_state_t* SurfaceComposerClient::lockLayerState(SurfaceID id)
 {
     layer_state_t* s;
     mLock.lock();
-    s = _get_state_l(id);
+    s = get_state_l(id);
     if (!s) mLock.unlock();
     return s;
 }
 
-void SurfaceComposerClient::_unlockLayerState()
+void SurfaceComposerClient::unlockLayerState()
 {
     mLock.unlock();
 }
 
 status_t SurfaceComposerClient::setPosition(SurfaceID id, int32_t x, int32_t y)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::ePositionChanged;
     s->x = x;
     s->y = y;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
 status_t SurfaceComposerClient::setSize(SurfaceID id, uint32_t w, uint32_t h)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eSizeChanged;
     s->w = w;
     s->h = h;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
 status_t SurfaceComposerClient::setLayer(SurfaceID id, int32_t z)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eLayerChanged;
     s->z = z;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
@@ -579,34 +583,34 @@
 status_t SurfaceComposerClient::setFlags(SurfaceID id,
         uint32_t flags, uint32_t mask)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eVisibilityChanged;
     s->flags &= ~mask;
     s->flags |= (flags & mask);
     s->mask |= mask;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
 status_t SurfaceComposerClient::setTransparentRegionHint(
         SurfaceID id, const Region& transparentRegion)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eTransparentRegionChanged;
     s->transparentRegion = transparentRegion;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
 status_t SurfaceComposerClient::setAlpha(SurfaceID id, float alpha)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eAlphaChanged;
     s->alpha = alpha;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
@@ -615,7 +619,7 @@
         float dsdx, float dtdx,
         float dsdy, float dtdy )
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eMatrixChanged;
     layer_state_t::matrix22_t matrix;
@@ -624,17 +628,17 @@
     matrix.dsdy = dsdy;
     matrix.dtdy = dtdy;
     s->matrix = matrix;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }
 
 status_t SurfaceComposerClient::setFreezeTint(SurfaceID id, uint32_t tint)
 {
-    layer_state_t* s = _lockLayerState(id);
+    layer_state_t* s = lockLayerState(id);
     if (!s) return BAD_INDEX;
     s->what |= ISurfaceComposer::eFreezeTintChanged;
     s->tint = tint;
-    _unlockLayerState();
+    unlockLayerState();
     return NO_ERROR;
 }