diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 737cc82..0a3534f 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+// #define LOG_NDEBUG 0
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
 #include <stdint.h>
@@ -134,8 +135,9 @@
         mRepaintEverything(0),
         mRenderEngine(NULL),
         mBootTime(systemTime()),
+        mBuiltinDisplays(),
         mVisibleRegionsDirty(false),
-        mHwWorkListDirty(false),
+        mGeometryInvalid(false),
         mAnimCompositionPending(false),
         mDebugRegion(0),
         mDebugDDMS(0),
@@ -263,6 +265,7 @@
 }
 
 void SurfaceFlinger::createBuiltinDisplayLocked(DisplayDevice::DisplayType type) {
+    ALOGV("createBuiltinDisplayLocked(%d)", type);
     ALOGW_IF(mBuiltinDisplays[type],
             "Overwriting display token for display type %d", type);
     mBuiltinDisplays[type] = new BBinder();
@@ -442,80 +445,48 @@
     ALOGI(  "SurfaceFlinger's main thread ready to run. "
             "Initializing graphics H/W...");
 
+    { // Autolock scope
+        Mutex::Autolock _l(mStateLock);
+
+        // initialize EGL for the default display
+        mEGLDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+        eglInitialize(mEGLDisplay, NULL, NULL);
+
+        // start the EventThread
+        sp<VSyncSource> vsyncSrc = new DispSyncSource(&mPrimaryDispSync,
+                vsyncPhaseOffsetNs, true, "app");
+        mEventThread = new EventThread(vsyncSrc);
+        sp<VSyncSource> sfVsyncSrc = new DispSyncSource(&mPrimaryDispSync,
+                sfVsyncPhaseOffsetNs, true, "sf");
+        mSFEventThread = new EventThread(sfVsyncSrc);
+        mEventQueue.setEventThread(mSFEventThread);
+
+        // Get a RenderEngine for the given display / config (can't fail)
+        mRenderEngine = RenderEngine::create(mEGLDisplay,
+                HAL_PIXEL_FORMAT_RGBA_8888);
+    }
+
+    // Drop the state lock while we initialize the hardware composer. We drop
+    // the lock because on creation, it will call back into SurfaceFlinger to
+    // initialize the primary display.
+    mHwc = new HWComposer(this);
+    mHwc->setEventHandler(static_cast<HWComposer::EventHandler*>(this));
+
     Mutex::Autolock _l(mStateLock);
 
-    // initialize EGL for the default display
-    mEGLDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
-    eglInitialize(mEGLDisplay, NULL, NULL);
-
-    // start the EventThread
-    sp<VSyncSource> vsyncSrc = new DispSyncSource(&mPrimaryDispSync,
-            vsyncPhaseOffsetNs, true, "app");
-    mEventThread = new EventThread(vsyncSrc);
-    sp<VSyncSource> sfVsyncSrc = new DispSyncSource(&mPrimaryDispSync,
-            sfVsyncPhaseOffsetNs, true, "sf");
-    mSFEventThread = new EventThread(sfVsyncSrc);
-    mEventQueue.setEventThread(mSFEventThread);
-
-    // Initialize the H/W composer object.  There may or may not be an
-    // actual hardware composer underneath.
-    mHwc = new HWComposer(this,
-            *static_cast<HWComposer::EventHandler *>(this));
-
-    // get a RenderEngine for the given display / config (can't fail)
-    mRenderEngine = RenderEngine::create(mEGLDisplay, mHwc->getVisualID());
-
     // retrieve the EGL context that was selected/created
     mEGLContext = mRenderEngine->getEGLContext();
 
     LOG_ALWAYS_FATAL_IF(mEGLContext == EGL_NO_CONTEXT,
             "couldn't create EGLContext");
 
-    // initialize our non-virtual displays
-    for (size_t i=0 ; i<DisplayDevice::NUM_BUILTIN_DISPLAY_TYPES ; i++) {
-        DisplayDevice::DisplayType type((DisplayDevice::DisplayType)i);
-        // set-up the displays that are already connected
-        if (mHwc->isConnected(i) || type==DisplayDevice::DISPLAY_PRIMARY) {
-            // All non-virtual displays are currently considered secure.
-            bool isSecure = true;
-            createBuiltinDisplayLocked(type);
-            wp<IBinder> token = mBuiltinDisplays[i];
-
-            sp<IGraphicBufferProducer> producer;
-            sp<IGraphicBufferConsumer> consumer;
-            BufferQueue::createBufferQueue(&producer, &consumer,
-                    new GraphicBufferAlloc());
-
-            sp<FramebufferSurface> fbs = new FramebufferSurface(*mHwc, i,
-                    consumer);
-            int32_t hwcId = allocateHwcDisplayId(type);
-            sp<DisplayDevice> hw = new DisplayDevice(this,
-                    type, hwcId, mHwc->getFormat(hwcId), isSecure, token,
-                    fbs, producer,
-                    mRenderEngine->getEGLConfig());
-            if (i > DisplayDevice::DISPLAY_PRIMARY) {
-                // FIXME: currently we don't get blank/unblank requests
-                // for displays other than the main display, so we always
-                // assume a connected display is unblanked.
-                ALOGD("marking display %zu as acquired/unblanked", i);
-                hw->setPowerMode(HWC_POWER_MODE_NORMAL);
-            }
-            mDisplays.add(token, hw);
-        }
-    }
-
-    // make the GLContext current so that we can create textures when creating Layers
-    // (which may happens before we render something)
+    // make the GLContext current so that we can create textures when creating
+    // Layers (which may happens before we render something)
     getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext);
 
     mEventControlThread = new EventControlThread(this);
     mEventControlThread->run("EventControl", PRIORITY_URGENT_DISPLAY);
 
-    // set a fake vsync period if there is no HWComposer
-    if (mHwc->initCheck() != NO_ERROR) {
-        mPrimaryDispSync.setPeriod(16666667);
-    }
-
     // initialize our drawing state
     mDrawingState = mCurrentState;
 
@@ -524,11 +495,8 @@
 
     // start boot animation
     startBootAnim();
-}
 
-int32_t SurfaceFlinger::allocateHwcDisplayId(DisplayDevice::DisplayType type) {
-    return (uint32_t(type) < DisplayDevice::NUM_BUILTIN_DISPLAY_TYPES) ?
-            type : mHwc->allocateDisplayId();
+    ALOGV("Done initializing");
 }
 
 void SurfaceFlinger::startBootAnim() {
@@ -594,14 +562,11 @@
 
     configs->clear();
 
-    const Vector<HWComposer::DisplayConfig>& hwConfigs =
-            getHwComposer().getConfigs(type);
-    for (size_t c = 0; c < hwConfigs.size(); ++c) {
-        const HWComposer::DisplayConfig& hwConfig = hwConfigs[c];
+    for (const auto& hwConfig : getHwComposer().getConfigs(type)) {
         DisplayInfo info = DisplayInfo();
 
-        float xdpi = hwConfig.xdpi;
-        float ydpi = hwConfig.ydpi;
+        float xdpi = hwConfig->getDpiX();
+        float ydpi = hwConfig->getDpiY();
 
         if (type == DisplayDevice::DISPLAY_PRIMARY) {
             // The density of the device is provided by a build property
@@ -629,13 +594,15 @@
             info.orientation = 0;
         }
 
-        info.w = hwConfig.width;
-        info.h = hwConfig.height;
+        info.w = hwConfig->getWidth();
+        info.h = hwConfig->getHeight();
         info.xdpi = xdpi;
         info.ydpi = ydpi;
-        info.fps = float(1e9 / hwConfig.refresh);
+        info.fps = 1e9 / hwConfig->getVsyncPeriod();
         info.appVsyncOffset = VSYNC_EVENT_PHASE_OFFSET_NS;
-        info.colorTransform = hwConfig.colorTransform;
+
+        // TODO: Hook this back up
+        info.colorTransform = 0;
 
         // This is how far in advance a buffer must be queued for
         // presentation at a given time.  If you want a buffer to appear
@@ -649,8 +616,8 @@
         //
         // We add an additional 1ms to allow for processing time and
         // differences between the ideal and actual refresh rate.
-        info.presentationDeadline =
-                hwConfig.refresh - SF_VSYNC_EVENT_PHASE_OFFSET_NS + 1000000;
+        info.presentationDeadline = hwConfig->getVsyncPeriod() -
+                SF_VSYNC_EVENT_PHASE_OFFSET_NS + 1000000;
 
         // All non-virtual displays are currently considered secure.
         info.secure = true;
@@ -812,8 +779,8 @@
         return;
     }
 
-    const nsecs_t period =
-            getHwComposer().getRefreshPeriod(HWC_DISPLAY_PRIMARY);
+    const auto& activeConfig = mHwc->getActiveConfig(HWC_DISPLAY_PRIMARY);
+    const nsecs_t period = activeConfig->getVsyncPeriod();
 
     mPrimaryDispSync.reset();
     mPrimaryDispSync.setPeriod(period);
@@ -839,7 +806,7 @@
     }
 }
 
-void SurfaceFlinger::onVSyncReceived(int type, nsecs_t timestamp) {
+void SurfaceFlinger::onVSyncReceived(int32_t type, nsecs_t timestamp) {
     bool needsHwVsync = false;
 
     { // Scope for the lock
@@ -856,19 +823,34 @@
     }
 }
 
-void SurfaceFlinger::onHotplugReceived(int type, bool connected) {
-    if (mEventThread == NULL) {
-        // This is a temporary workaround for b/7145521.  A non-null pointer
-        // does not mean EventThread has finished initializing, so this
-        // is not a correct fix.
-        ALOGW("WARNING: EventThread not started, ignoring hotplug");
-        return;
-    }
+void SurfaceFlinger::onHotplugReceived(int32_t disp, bool connected) {
+    ALOGV("onHotplugReceived(%d, %s)", disp, connected ? "true" : "false");
+    if (disp == DisplayDevice::DISPLAY_PRIMARY) {
+        Mutex::Autolock lock(mStateLock);
 
-    if (uint32_t(type) < DisplayDevice::NUM_BUILTIN_DISPLAY_TYPES) {
+        // All non-virtual displays are currently considered secure.
+        bool isSecure = true;
+
+        int32_t type = DisplayDevice::DISPLAY_PRIMARY;
+        createBuiltinDisplayLocked(DisplayDevice::DISPLAY_PRIMARY);
+        wp<IBinder> token = mBuiltinDisplays[type];
+
+        sp<IGraphicBufferProducer> producer;
+        sp<IGraphicBufferConsumer> consumer;
+        BufferQueue::createBufferQueue(&producer, &consumer,
+                new GraphicBufferAlloc());
+
+        sp<FramebufferSurface> fbs = new FramebufferSurface(*mHwc,
+                DisplayDevice::DISPLAY_PRIMARY, consumer);
+        sp<DisplayDevice> hw = new DisplayDevice(this,
+                DisplayDevice::DISPLAY_PRIMARY, disp, isSecure, token, fbs,
+                producer, mRenderEngine->getEGLConfig());
+        mDisplays.add(token, hw);
+    } else {
+        auto type = DisplayDevice::DISPLAY_EXTERNAL;
         Mutex::Autolock _l(mStateLock);
         if (connected) {
-            createBuiltinDisplayLocked((DisplayDevice::DisplayType)type);
+            createBuiltinDisplayLocked(type);
         } else {
             mCurrentState.displays.removeItem(mBuiltinDisplays[type]);
             mBuiltinDisplays[type].clear();
@@ -879,9 +861,10 @@
     }
 }
 
-void SurfaceFlinger::eventControl(int disp, int event, int enabled) {
+void SurfaceFlinger::setVsyncEnabled(int disp, int enabled) {
     ATRACE_CALL();
-    getHwComposer().eventControl(disp, event, enabled);
+    getHwComposer().setVsyncEnabled(disp,
+            enabled ? HWC2::Vsync::Enable : HWC2::Vsync::Disable);
 }
 
 void SurfaceFlinger::onMessageReceived(int32_t what) {
@@ -950,6 +933,12 @@
         postComposition();
     }
 
+    // Release any buffers which were replaced this frame
+    for (auto& layer : mLayersWithQueuedFrames) {
+        layer->releasePendingBuffer();
+    }
+    mLayersWithQueuedFrames.clear();
+
     previousExpectedPresent = mPrimaryDispSync.computeNextRefresh(0);
 }
 
@@ -974,7 +963,6 @@
                 RenderEngine& engine(getRenderEngine());
                 engine.fillRegionWithColor(dirtyRegion, height, 1, 0, 1, 1);
 
-                hw->compositionComplete();
                 hw->swapBuffers(getHwComposer());
             }
         }
@@ -986,15 +974,18 @@
         usleep(mDebugRegion * 1000);
     }
 
-    HWComposer& hwc(getHwComposer());
-    if (hwc.initCheck() == NO_ERROR) {
-        status_t err = hwc.prepare();
-        ALOGE_IF(err, "HWComposer::prepare failed (%s)", strerror(-err));
+    for (size_t displayId = 0; displayId < mDisplays.size(); ++displayId) {
+        status_t result = mDisplays[displayId]->prepareFrame(*mHwc);
+        ALOGE_IF(result != NO_ERROR, "prepareFrame for display %zd failed:"
+                " %d (%s)", displayId, result, strerror(-result));
     }
 }
 
 void SurfaceFlinger::preComposition()
 {
+    ATRACE_CALL();
+    ALOGV("preComposition");
+
     bool needExtraInvalidate = false;
     const LayerVector& layers(mDrawingState.layersSortedByZ);
     const size_t count = layers.size();
@@ -1010,14 +1001,16 @@
 
 void SurfaceFlinger::postComposition()
 {
+    ATRACE_CALL();
+    ALOGV("postComposition");
+
     const LayerVector& layers(mDrawingState.layersSortedByZ);
     const size_t count = layers.size();
     for (size_t i=0 ; i<count ; i++) {
         layers[i]->onPostComposition();
     }
 
-    const HWComposer& hwc = getHwComposer();
-    sp<Fence> presentFence = hwc.getDisplayFence(HWC_DISPLAY_PRIMARY);
+    sp<Fence> presentFence = mHwc->getRetireFence(HWC_DISPLAY_PRIMARY);
 
     if (presentFence->isValid()) {
         if (mPrimaryDispSync.addPresentFence(presentFence)) {
@@ -1042,7 +1035,8 @@
         } else {
             // The HWC doesn't support present fences, so use the refresh
             // timestamp instead.
-            nsecs_t presentTime = hwc.getRefreshTimestamp(HWC_DISPLAY_PRIMARY);
+            nsecs_t presentTime =
+                    mHwc->getRefreshTimestamp(HWC_DISPLAY_PRIMARY);
             mAnimFrameTracker.setActualPresentTime(presentTime);
         }
         mAnimFrameTracker.advanceFrame();
@@ -1070,6 +1064,9 @@
 }
 
 void SurfaceFlinger::rebuildLayerStacks() {
+    ATRACE_CALL();
+    ALOGV("rebuildLayerStacks");
+
     // rebuild the visible layer list per screen
     if (CC_UNLIKELY(mVisibleRegionsDirty)) {
         ATRACE_CALL();
@@ -1080,37 +1077,47 @@
         for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
             Region opaqueRegion;
             Region dirtyRegion;
-            Vector< sp<Layer> > layersSortedByZ;
-            const sp<DisplayDevice>& hw(mDisplays[dpy]);
-            const Transform& tr(hw->getTransform());
-            const Rect bounds(hw->getBounds());
-            if (hw->isDisplayOn()) {
+            Vector<sp<Layer>> layersSortedByZ;
+            const sp<DisplayDevice>& displayDevice(mDisplays[dpy]);
+            const Transform& tr(displayDevice->getTransform());
+            const Rect bounds(displayDevice->getBounds());
+            if (displayDevice->isDisplayOn()) {
                 SurfaceFlinger::computeVisibleRegions(layers,
-                        hw->getLayerStack(), dirtyRegion, opaqueRegion);
+                        displayDevice->getLayerStack(), dirtyRegion,
+                        opaqueRegion);
 
                 const size_t count = layers.size();
                 for (size_t i=0 ; i<count ; i++) {
                     const sp<Layer>& layer(layers[i]);
                     const Layer::State& s(layer->getDrawingState());
-                    if (s.layerStack == hw->getLayerStack()) {
+                    if (s.layerStack == displayDevice->getLayerStack()) {
                         Region drawRegion(tr.transform(
                                 layer->visibleNonTransparentRegion));
                         drawRegion.andSelf(bounds);
                         if (!drawRegion.isEmpty()) {
                             layersSortedByZ.add(layer);
+                        } else {
+                            // Clear out the HWC layer if this layer was
+                            // previously visible, but no longer is
+                            layer->setHwcLayer(displayDevice->getHwcDisplayId(),
+                                    nullptr);
                         }
                     }
                 }
             }
-            hw->setVisibleLayersSortedByZ(layersSortedByZ);
-            hw->undefinedRegion.set(bounds);
-            hw->undefinedRegion.subtractSelf(tr.transform(opaqueRegion));
-            hw->dirtyRegion.orSelf(dirtyRegion);
+            displayDevice->setVisibleLayersSortedByZ(layersSortedByZ);
+            displayDevice->undefinedRegion.set(bounds);
+            displayDevice->undefinedRegion.subtractSelf(
+                    tr.transform(opaqueRegion));
+            displayDevice->dirtyRegion.orSelf(dirtyRegion);
         }
     }
 }
 
 void SurfaceFlinger::setUpHWComposer() {
+    ATRACE_CALL();
+    ALOGV("setUpHWComposer");
+
     for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
         bool dirty = !mDisplays[dpy]->getDirtyRegion(false).isEmpty();
         bool empty = mDisplays[dpy]->getVisibleLayersSortedByZ().size() == 0;
@@ -1140,86 +1147,61 @@
         }
     }
 
-    HWComposer& hwc(getHwComposer());
-    if (hwc.initCheck() == NO_ERROR) {
-        // build the h/w work list
-        if (CC_UNLIKELY(mHwWorkListDirty)) {
-            mHwWorkListDirty = false;
-            for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
-                sp<const DisplayDevice> hw(mDisplays[dpy]);
-                const int32_t id = hw->getHwcDisplayId();
-                if (id >= 0) {
-                    const Vector< sp<Layer> >& currentLayers(
-                        hw->getVisibleLayersSortedByZ());
-                    const size_t count = currentLayers.size();
-                    if (hwc.createWorkList(id, count) == NO_ERROR) {
-                        HWComposer::LayerListIterator cur = hwc.begin(id);
-                        const HWComposer::LayerListIterator end = hwc.end(id);
-                        for (size_t i=0 ; cur!=end && i<count ; ++i, ++cur) {
-                            const sp<Layer>& layer(currentLayers[i]);
-                            layer->setGeometry(hw, *cur);
-                            if (mDebugDisableHWC || mDebugRegion || mDaltonize || mHasColorMatrix) {
-                                cur->setSkip(true);
-                            }
+    // build the h/w work list
+    if (CC_UNLIKELY(mGeometryInvalid)) {
+        mGeometryInvalid = false;
+        for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
+            sp<const DisplayDevice> displayDevice(mDisplays[dpy]);
+            const auto hwcId = displayDevice->getHwcDisplayId();
+            if (hwcId >= 0) {
+                const Vector<sp<Layer>>& currentLayers(
+                        displayDevice->getVisibleLayersSortedByZ());
+                bool foundLayerWithoutHwc = false;
+                for (auto& layer : currentLayers) {
+                    if (!layer->hasHwcLayer(hwcId)) {
+                        auto hwcLayer = mHwc->createLayer(hwcId);
+                        if (hwcLayer) {
+                            layer->setHwcLayer(hwcId, std::move(hwcLayer));
+                        } else {
+                            layer->forceClientComposition(hwcId);
+                            foundLayerWithoutHwc = true;
+                            continue;
                         }
                     }
-                }
-            }
-        }
 
-        // set the per-frame data
-        for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
-            sp<const DisplayDevice> hw(mDisplays[dpy]);
-            const int32_t id = hw->getHwcDisplayId();
-            if (id >= 0) {
-                const Vector< sp<Layer> >& currentLayers(
-                    hw->getVisibleLayersSortedByZ());
-                const size_t count = currentLayers.size();
-                HWComposer::LayerListIterator cur = hwc.begin(id);
-                const HWComposer::LayerListIterator end = hwc.end(id);
-                for (size_t i=0 ; cur!=end && i<count ; ++i, ++cur) {
-                    /*
-                     * update the per-frame h/w composer data for each layer
-                     * and build the transparent region of the FB
-                     */
-                    const sp<Layer>& layer(currentLayers[i]);
-                    layer->setPerFrameData(hw, *cur);
-                }
-            }
-        }
-
-        // If possible, attempt to use the cursor overlay on each display.
-        for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
-            sp<const DisplayDevice> hw(mDisplays[dpy]);
-            const int32_t id = hw->getHwcDisplayId();
-            if (id >= 0) {
-                const Vector< sp<Layer> >& currentLayers(
-                    hw->getVisibleLayersSortedByZ());
-                const size_t count = currentLayers.size();
-                HWComposer::LayerListIterator cur = hwc.begin(id);
-                const HWComposer::LayerListIterator end = hwc.end(id);
-                for (size_t i=0 ; cur!=end && i<count ; ++i, ++cur) {
-                    const sp<Layer>& layer(currentLayers[i]);
-                    if (layer->isPotentialCursor()) {
-                        cur->setIsCursorLayerHint();
-                        break;
+                    layer->setGeometry(displayDevice);
+                    if (mDebugDisableHWC || mDebugRegion || mDaltonize ||
+                            mHasColorMatrix) {
+                        layer->forceClientComposition(hwcId);
                     }
                 }
             }
         }
+    }
 
-        status_t err = hwc.prepare();
-        ALOGE_IF(err, "HWComposer::prepare failed (%s)", strerror(-err));
-
-        for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
-            sp<const DisplayDevice> hw(mDisplays[dpy]);
-            hw->prepareFrame(hwc);
+    // Set the per-frame data
+    for (size_t displayId = 0; displayId < mDisplays.size(); ++displayId) {
+        auto& displayDevice = mDisplays[displayId];
+        const auto hwcId = displayDevice->getHwcDisplayId();
+        if (hwcId < 0) {
+            continue;
         }
+        for (auto& layer : displayDevice->getVisibleLayersSortedByZ()) {
+            layer->setPerFrameData(displayDevice);
+        }
+    }
+
+    for (size_t displayId = 0; displayId < mDisplays.size(); ++displayId) {
+        status_t result = mDisplays[displayId]->prepareFrame(*mHwc);
+        ALOGE_IF(result != NO_ERROR, "prepareFrame for display %zd failed:"
+                " %d (%s)", displayId, result, strerror(-result));
     }
 }
 
 void SurfaceFlinger::doComposition() {
     ATRACE_CALL();
+    ALOGV("doComposition");
+
     const bool repaintEverything = android_atomic_and(0, &mRepaintEverything);
     for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
         const sp<DisplayDevice>& hw(mDisplays[dpy]);
@@ -1234,8 +1216,6 @@
             hw->flip(hw->swapRegion);
             hw->swapRegion.clear();
         }
-        // inform the h/w that we're done compositing
-        hw->compositionComplete();
     }
     postFramebuffer();
 }
@@ -1243,43 +1223,37 @@
 void SurfaceFlinger::postFramebuffer()
 {
     ATRACE_CALL();
+    ALOGV("postFramebuffer");
 
     const nsecs_t now = systemTime();
     mDebugInSwapBuffers = now;
 
-    HWComposer& hwc(getHwComposer());
-    if (hwc.initCheck() == NO_ERROR) {
-        if (!hwc.supportsFramebufferTarget()) {
-            // EGL spec says:
-            //   "surface must be bound to the calling thread's current context,
-            //    for the current rendering API."
-            getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext);
+    for (size_t displayId = 0; displayId < mDisplays.size(); ++displayId) {
+        auto& displayDevice = mDisplays[displayId];
+        const auto hwcId = displayDevice->getHwcDisplayId();
+        if (hwcId >= 0) {
+            mHwc->commit(hwcId);
         }
-        hwc.commit();
-    }
-
-    // make the default display current because the VirtualDisplayDevice code cannot
-    // deal with dequeueBuffer() being called outside of the composition loop; however
-    // the code below can call glFlush() which is allowed (and does in some case) call
-    // dequeueBuffer().
-    getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext);
-
-    for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
-        sp<const DisplayDevice> hw(mDisplays[dpy]);
-        const Vector< sp<Layer> >& currentLayers(hw->getVisibleLayersSortedByZ());
-        hw->onSwapBuffersCompleted(hwc);
-        const size_t count = currentLayers.size();
-        int32_t id = hw->getHwcDisplayId();
-        if (id >=0 && hwc.initCheck() == NO_ERROR) {
-            HWComposer::LayerListIterator cur = hwc.begin(id);
-            const HWComposer::LayerListIterator end = hwc.end(id);
-            for (size_t i = 0; cur != end && i < count; ++i, ++cur) {
-                currentLayers[i]->onLayerDisplayed(hw, &*cur);
+        if (displayId == 0) {
+            // Make the default display current because the VirtualDisplayDevice
+            // code cannot deal with dequeueBuffer() being called outside of the
+            // composition loop; however the code below can call glFlush() which
+            // is allowed to (and does in some case) call dequeueBuffer().
+            displayDevice->makeCurrent(mEGLDisplay, mEGLContext);
+        }
+        displayDevice->onSwapBuffersCompleted();
+        for (auto& layer : displayDevice->getVisibleLayersSortedByZ()) {
+            sp<Fence> releaseFence = Fence::NO_FENCE;
+            if (layer->getCompositionType(hwcId) == HWC2::Composition::Client) {
+                releaseFence = displayDevice->getClientTargetAcquireFence();
+            } else {
+                auto hwcLayer = layer->getHwcLayer(hwcId);
+                releaseFence = mHwc->getLayerReleaseFence(hwcId, hwcLayer);
             }
-        } else {
-            for (size_t i = 0; i < count; i++) {
-                currentLayers[i]->onLayerDisplayed(hw, NULL);
-            }
+            layer->onLayerDisplayed(releaseFence);
+        }
+        if (hwcId >= 0) {
+            mHwc->clearReleaseFences(hwcId);
         }
     }
 
@@ -1439,7 +1413,7 @@
                     BufferQueue::createBufferQueue(&bqProducer, &bqConsumer,
                             new GraphicBufferAlloc());
 
-                    int32_t hwcDisplayId = -1;
+                    int32_t hwcId = -1;
                     if (state.isVirtualDisplay()) {
                         // Virtual displays without a surface are dormant:
                         // they have external state (layer stack, projection,
@@ -1456,15 +1430,14 @@
                                     NATIVE_WINDOW_HEIGHT, &height);
                             ALOGE_IF(status != NO_ERROR,
                                     "Unable to query height (%d)", status);
-                            if (MAX_VIRTUAL_DISPLAY_DIMENSION == 0 ||
-                                    (width <= MAX_VIRTUAL_DISPLAY_DIMENSION &&
-                                     height <= MAX_VIRTUAL_DISPLAY_DIMENSION)) {
-                                hwcDisplayId = allocateHwcDisplayId(state.type);
-                            }
 
-                            sp<VirtualDisplaySurface> vds = new VirtualDisplaySurface(
-                                    *mHwc, hwcDisplayId, state.surface,
-                                    bqProducer, bqConsumer, state.displayName);
+                            mHwc->allocateVirtualDisplay(width, height,
+                                    &hwcId);
+
+                            sp<VirtualDisplaySurface> vds =
+                                    new VirtualDisplaySurface(*mHwc,
+                                            hwcId, state.surface, bqProducer,
+                                            bqConsumer, state.displayName);
 
                             dispSurface = vds;
                             producer = vds;
@@ -1474,33 +1447,30 @@
                                 "adding a supported display, but rendering "
                                 "surface is provided (%p), ignoring it",
                                 state.surface.get());
-                        hwcDisplayId = allocateHwcDisplayId(state.type);
-                        // for supported (by hwc) displays we provide our
-                        // own rendering surface
-                        dispSurface = new FramebufferSurface(*mHwc, state.type,
-                                bqConsumer);
-                        producer = bqProducer;
+                        if (state.type == DisplayDevice::DISPLAY_EXTERNAL) {
+                            hwcId = DisplayDevice::DISPLAY_EXTERNAL;
+                            dispSurface = new FramebufferSurface(*mHwc,
+                                    DisplayDevice::DISPLAY_EXTERNAL,
+                                    bqConsumer);
+                            producer = bqProducer;
+                        } else {
+                            ALOGE("Attempted to add non-external non-virtual"
+                                    " display");
+                        }
                     }
 
                     const wp<IBinder>& display(curr.keyAt(i));
                     if (dispSurface != NULL) {
                         sp<DisplayDevice> hw = new DisplayDevice(this,
-                                state.type, hwcDisplayId,
-                                mHwc->getFormat(hwcDisplayId), state.isSecure,
-                                display, dispSurface, producer,
+                                state.type, hwcId, state.isSecure, display,
+                                dispSurface, producer,
                                 mRenderEngine->getEGLConfig());
                         hw->setLayerStack(state.layerStack);
                         hw->setProjection(state.orientation,
                                 state.viewport, state.frame);
                         hw->setDisplayName(state.displayName);
                         mDisplays.add(display, hw);
-                        if (state.isVirtualDisplay()) {
-                            if (hwcDisplayId >= 0) {
-                                mHwc->setVirtualDisplayProperties(hwcDisplayId,
-                                        hw->getWidth(), hw->getHeight(),
-                                        hw->getFormat());
-                            }
-                        } else {
+                        if (!state.isVirtualDisplay()) {
                             mEventThread->onHotplugReceived(state.type, true);
                         }
                     }
@@ -1607,26 +1577,14 @@
 
 void SurfaceFlinger::updateCursorAsync()
 {
-    HWComposer& hwc(getHwComposer());
-    for (size_t dpy=0 ; dpy<mDisplays.size() ; dpy++) {
-        sp<const DisplayDevice> hw(mDisplays[dpy]);
-        const int32_t id = hw->getHwcDisplayId();
-        if (id < 0) {
+    for (size_t displayId = 0; displayId < mDisplays.size(); ++displayId) {
+        auto& displayDevice = mDisplays[displayId];
+        if (displayDevice->getHwcDisplayId() < 0) {
             continue;
         }
-        const Vector< sp<Layer> >& currentLayers(
-            hw->getVisibleLayersSortedByZ());
-        const size_t count = currentLayers.size();
-        HWComposer::LayerListIterator cur = hwc.begin(id);
-        const HWComposer::LayerListIterator end = hwc.end(id);
-        for (size_t i=0 ; cur!=end && i<count ; ++i, ++cur) {
-            if (cur->getCompositionType() != HWC_CURSOR_OVERLAY) {
-                continue;
-            }
-            const sp<Layer>& layer(currentLayers[i]);
-            Rect cursorPos = layer->getPosition(hw);
-            hwc.setCursorPositionAsync(id, cursorPos);
-            break;
+
+        for (auto& layer : displayDevice->getVisibleLayersSortedByZ()) {
+            layer->updateCursorPosition(displayDevice);
         }
     }
 }
@@ -1656,6 +1614,7 @@
         Region& outDirtyRegion, Region& outOpaqueRegion)
 {
     ATRACE_CALL();
+    ALOGV("computeVisibleRegions");
 
     Region aboveOpaqueLayers;
     Region aboveCoveredLayers;
@@ -1729,7 +1688,7 @@
 
                 // compute the opaque region
                 const int32_t layerOrientation = s.transform.getOrientation();
-                if (s.alpha==255 && !translucent &&
+                if (s.alpha == 1.0f && !translucent &&
                         ((layerOrientation & Transform::ROT_INVALID) == false)) {
                     // the opaque region is the layer's footprint
                     opaqueRegion = visibleRegion;
@@ -1802,6 +1761,8 @@
 
 bool SurfaceFlinger::handlePageFlip()
 {
+    ALOGV("handlePageFlip");
+
     Region dirtyRegion;
 
     bool visibleRegions = false;
@@ -1817,13 +1778,12 @@
     // 3.) Layer 1 is latched.
     // Display is now waiting on Layer 1's frame, which is behind layer 0's
     // second frame. But layer 0's second frame could be waiting on display.
-    Vector<Layer*> layersWithQueuedFrames;
     for (size_t i = 0, count = layers.size(); i<count ; i++) {
         const sp<Layer>& layer(layers[i]);
         if (layer->hasQueuedFrame()) {
             frameQueued = true;
             if (layer->shouldPresentNow(mPrimaryDispSync)) {
-                layersWithQueuedFrames.push_back(layer.get());
+                mLayersWithQueuedFrames.push_back(layer.get());
             } else {
                 layer->useEmptyDamage();
             }
@@ -1831,8 +1791,7 @@
             layer->useEmptyDamage();
         }
     }
-    for (size_t i = 0, count = layersWithQueuedFrames.size() ; i<count ; i++) {
-        Layer* layer = layersWithQueuedFrames[i];
+    for (auto& layer : mLayersWithQueuedFrames) {
         const Region dirty(layer->latchBuffer(visibleRegions));
         layer->useSurfaceDamage();
         const Layer::State& s(layer->getDrawingState());
@@ -1844,17 +1803,17 @@
     // If we will need to wake up at some time in the future to deal with a
     // queued frame that shouldn't be displayed during this vsync period, wake
     // up during the next vsync period to check again.
-    if (frameQueued && layersWithQueuedFrames.empty()) {
+    if (frameQueued && mLayersWithQueuedFrames.empty()) {
         signalLayerUpdate();
     }
 
     // Only continue with the refresh if there is actually new work to do
-    return !layersWithQueuedFrames.empty();
+    return !mLayersWithQueuedFrames.empty();
 }
 
 void SurfaceFlinger::invalidateHwcGeometry()
 {
-    mHwWorkListDirty = true;
+    mGeometryInvalid = true;
 }
 
 
@@ -1867,9 +1826,12 @@
     // 2) There is work to be done (the dirty region isn't empty)
     bool isHwcDisplay = hw->getHwcDisplayId() >= 0;
     if (!isHwcDisplay && inDirtyRegion.isEmpty()) {
+        ALOGV("Skipping display composition");
         return;
     }
 
+    ALOGV("doDisplayComposition");
+
     Region dirtyRegion(inDirtyRegion);
 
     // compute the invalid region
@@ -1915,19 +1877,19 @@
     hw->swapBuffers(getHwComposer());
 }
 
-bool SurfaceFlinger::doComposeSurfaces(const sp<const DisplayDevice>& hw, const Region& dirty)
+bool SurfaceFlinger::doComposeSurfaces(
+        const sp<const DisplayDevice>& displayDevice, const Region& dirty)
 {
-    RenderEngine& engine(getRenderEngine());
-    const int32_t id = hw->getHwcDisplayId();
-    HWComposer& hwc(getHwComposer());
-    HWComposer::LayerListIterator cur = hwc.begin(id);
-    const HWComposer::LayerListIterator end = hwc.end(id);
+    ALOGV("doComposeSurfaces");
 
-    bool hasGlesComposition = hwc.hasGlesComposition(id);
-    if (hasGlesComposition) {
-        if (!hw->makeCurrent(mEGLDisplay, mEGLContext)) {
+    const auto hwcId = displayDevice->getHwcDisplayId();
+    bool hasClientComposition = mHwc->hasClientComposition(hwcId);
+    if (hasClientComposition) {
+        ALOGV("hasClientComposition");
+
+        if (!displayDevice->makeCurrent(mEGLDisplay, mEGLContext)) {
             ALOGW("DisplayDevice::makeCurrent failed. Aborting surface composition for display %s",
-                  hw->getDisplayName().string());
+                  displayDevice->getDisplayName().string());
             eglMakeCurrent(mEGLDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
             if(!getDefaultDisplayDevice()->makeCurrent(mEGLDisplay, mEGLContext)) {
               ALOGE("DisplayDevice::makeCurrent on default display failed. Aborting.");
@@ -1936,25 +1898,25 @@
         }
 
         // Never touch the framebuffer if we don't have any framebuffer layers
-        const bool hasHwcComposition = hwc.hasHwcComposition(id);
-        if (hasHwcComposition) {
+        const bool hasDeviceComposition = mHwc->hasDeviceComposition(hwcId);
+        if (hasDeviceComposition) {
             // when using overlays, we assume a fully transparent framebuffer
             // NOTE: we could reduce how much we need to clear, for instance
             // remove where there are opaque FB layers. however, on some
             // GPUs doing a "clean slate" clear might be more efficient.
             // We'll revisit later if needed.
-            engine.clearWithColor(0, 0, 0, 0);
+            mRenderEngine->clearWithColor(0, 0, 0, 0);
         } else {
             // we start with the whole screen area
-            const Region bounds(hw->getBounds());
+            const Region bounds(displayDevice->getBounds());
 
             // we remove the scissor part
             // we're left with the letterbox region
             // (common case is that letterbox ends-up being empty)
-            const Region letterbox(bounds.subtract(hw->getScissor()));
+            const Region letterbox(bounds.subtract(displayDevice->getScissor()));
 
             // compute the area to clear
-            Region region(hw->undefinedRegion.merge(letterbox));
+            Region region(displayDevice->undefinedRegion.merge(letterbox));
 
             // but limit it to the dirty region
             region.andSelf(dirty);
@@ -1962,24 +1924,24 @@
             // screen is already cleared here
             if (!region.isEmpty()) {
                 // can happen with SurfaceView
-                drawWormhole(hw, region);
+                drawWormhole(displayDevice, region);
             }
         }
 
-        if (hw->getDisplayType() != DisplayDevice::DISPLAY_PRIMARY) {
+        if (displayDevice->getDisplayType() != DisplayDevice::DISPLAY_PRIMARY) {
             // just to be on the safe side, we don't set the
             // scissor on the main display. It should never be needed
             // anyways (though in theory it could since the API allows it).
-            const Rect& bounds(hw->getBounds());
-            const Rect& scissor(hw->getScissor());
+            const Rect& bounds(displayDevice->getBounds());
+            const Rect& scissor(displayDevice->getScissor());
             if (scissor != bounds) {
                 // scissor doesn't match the screen's dimensions, so we
                 // need to clear everything outside of it and enable
                 // the GL scissor so we don't draw anything where we shouldn't
 
                 // enable scissor for this frame
-                const uint32_t height = hw->getHeight();
-                engine.setScissor(scissor.left, height - scissor.bottom,
+                const uint32_t height = displayDevice->getHeight();
+                mRenderEngine->setScissor(scissor.left, height - scissor.bottom,
                         scissor.getWidth(), scissor.getHeight());
             }
         }
@@ -1989,57 +1951,57 @@
      * and then, render the layers targeted at the framebuffer
      */
 
-    const Vector< sp<Layer> >& layers(hw->getVisibleLayersSortedByZ());
-    const size_t count = layers.size();
-    const Transform& tr = hw->getTransform();
-    if (cur != end) {
+    ALOGV("Rendering client layers");
+    const Transform& displayTransform = displayDevice->getTransform();
+    if (hwcId >= 0) {
         // we're using h/w composer
-        for (size_t i=0 ; i<count && cur!=end ; ++i, ++cur) {
-            const sp<Layer>& layer(layers[i]);
-            const Region clip(dirty.intersect(tr.transform(layer->visibleRegion)));
+        bool firstLayer = true;
+        for (auto& layer : displayDevice->getVisibleLayersSortedByZ()) {
+            const Region clip(dirty.intersect(
+                    displayTransform.transform(layer->visibleRegion)));
+            ALOGV("Layer: %s", layer->getName().string());
+            ALOGV("  Composition type: %s",
+                    to_string(layer->getCompositionType(hwcId)).c_str());
             if (!clip.isEmpty()) {
-                switch (cur->getCompositionType()) {
-                    case HWC_CURSOR_OVERLAY:
-                    case HWC_OVERLAY: {
+                switch (layer->getCompositionType(hwcId)) {
+                    case HWC2::Composition::Cursor:
+                    case HWC2::Composition::Device:
+                    case HWC2::Composition::SolidColor: {
                         const Layer::State& state(layer->getDrawingState());
-                        if ((cur->getHints() & HWC_HINT_CLEAR_FB)
-                                && i
-                                && layer->isOpaque(state) && (state.alpha == 0xFF)
-                                && hasGlesComposition) {
+                        if (layer->getClearClientTarget(hwcId) && !firstLayer &&
+                                layer->isOpaque(state) && (state.alpha == 1.0f)
+                                && hasClientComposition) {
                             // never clear the very first layer since we're
                             // guaranteed the FB is already cleared
-                            layer->clearWithOpenGL(hw, clip);
+                            layer->clearWithOpenGL(displayDevice, clip);
                         }
                         break;
                     }
-                    case HWC_FRAMEBUFFER: {
-                        layer->draw(hw, clip);
+                    case HWC2::Composition::Client: {
+                        layer->draw(displayDevice, clip);
                         break;
                     }
-                    case HWC_FRAMEBUFFER_TARGET: {
-                        // this should not happen as the iterator shouldn't
-                        // let us get there.
-                        ALOGW("HWC_FRAMEBUFFER_TARGET found in hwc list (index=%zu)", i);
+                    default:
                         break;
-                    }
                 }
+            } else {
+                ALOGV("  Skipping for empty clip");
             }
-            layer->setAcquireFence(hw, *cur);
+            firstLayer = false;
         }
     } else {
         // we're not using h/w composer
-        for (size_t i=0 ; i<count ; ++i) {
-            const sp<Layer>& layer(layers[i]);
+        for (auto& layer : displayDevice->getVisibleLayersSortedByZ()) {
             const Region clip(dirty.intersect(
-                    tr.transform(layer->visibleRegion)));
+                    displayTransform.transform(layer->visibleRegion)));
             if (!clip.isEmpty()) {
-                layer->draw(hw, clip);
+                layer->draw(displayDevice, clip);
             }
         }
     }
 
     // disable scissor at the end of the frame
-    engine.disableScissor();
+    mRenderEngine->disableScissor();
     return true;
 }
 
@@ -2255,7 +2217,7 @@
             }
         }
         if (what & layer_state_t::eAlphaChanged) {
-            if (layer->setAlpha(uint8_t(255.0f*s.alpha+0.5f)))
+            if (layer->setAlpha(s.alpha))
                 flags |= eTraversalNeeded;
         }
         if (what & layer_state_t::eMatrixChanged) {
@@ -2423,8 +2385,8 @@
     setTransactionState(state, displays, 0);
     setPowerModeInternal(getDisplayDevice(d.token), HWC_POWER_MODE_NORMAL);
 
-    const nsecs_t period =
-            getHwComposer().getRefreshPeriod(HWC_DISPLAY_PRIMARY);
+    const auto& activeConfig = mHwc->getActiveConfig(HWC_DISPLAY_PRIMARY);
+    const nsecs_t period = activeConfig->getVsyncPeriod();
     mAnimFrameTracker.setDisplayRefreshPeriod(period);
 }
 
@@ -2611,8 +2573,8 @@
         index++;
     }
 
-    const nsecs_t period =
-            getHwComposer().getRefreshPeriod(HWC_DISPLAY_PRIMARY);
+    const auto& activeConfig = mHwc->getActiveConfig(HWC_DISPLAY_PRIMARY);
+    const nsecs_t period = activeConfig->getVsyncPeriod();
     result.appendFormat("%" PRId64 "\n", period);
 
     if (name.isEmpty()) {
@@ -2734,13 +2696,15 @@
     result.append(SyncFeatures::getInstance().toString());
     result.append("\n");
 
+    const auto& activeConfig = mHwc->getActiveConfig(HWC_DISPLAY_PRIMARY);
+
     colorizer.bold(result);
     result.append("DispSync configuration: ");
     colorizer.reset(result);
     result.appendFormat("app phase %" PRId64 " ns, sf phase %" PRId64 " ns, "
             "present offset %d ns (refresh %" PRId64 " ns)",
-        vsyncPhaseOffsetNs, sfVsyncPhaseOffsetNs, PRESENT_TIME_OFFSET_FROM_VSYNC_NS,
-        mHwc->getRefreshPeriod(HWC_DISPLAY_PRIMARY));
+        vsyncPhaseOffsetNs, sfVsyncPhaseOffsetNs,
+        PRESENT_TIME_OFFSET_FROM_VSYNC_NS, activeConfig->getVsyncPeriod());
     result.append("\n");
 
     // Dump static screen stats
@@ -2808,9 +2772,9 @@
             mLastSwapBufferTime/1000.0,
             mLastTransactionTime/1000.0,
             mTransactionFlags,
-            1e9 / hwc.getRefreshPeriod(HWC_DISPLAY_PRIMARY),
-            hwc.getDpiX(HWC_DISPLAY_PRIMARY),
-            hwc.getDpiY(HWC_DISPLAY_PRIMARY),
+            1e9 / activeConfig->getVsyncPeriod(),
+            activeConfig->getDpiX(),
+            activeConfig->getDpiY(),
             !mGpuToCpuSupported);
 
     result.appendFormat("  eglSwapBuffers time: %f us\n",
@@ -2830,10 +2794,10 @@
     colorizer.bold(result);
     result.append("h/w composer state:\n");
     colorizer.reset(result);
-    result.appendFormat("  h/w composer %s and %s\n",
-            hwc.initCheck()==NO_ERROR ? "present" : "not present",
-                    (mDebugDisableHWC || mDebugRegion || mDaltonize
-                            || mHasColorMatrix) ? "disabled" : "enabled");
+    bool hwcDisabled = mDebugDisableHWC || mDebugRegion || mDaltonize ||
+            mHasColorMatrix;
+    result.appendFormat("  h/w composer %s\n",
+            hwcDisabled ? "disabled" : "enabled");
     hwc.dump(result);
 
     /*
@@ -3338,8 +3302,6 @@
         }
     }
 
-    // compositionComplete is needed for older driver
-    hw->compositionComplete();
     hw->setViewportAndProjection();
 }
 
@@ -3516,7 +3478,7 @@
             const bool visible = (state.layerStack == hw->getLayerStack())
                                 && (state.z >= minLayerZ && state.z <= maxLayerZ)
                                 && (layer->isVisible());
-            ALOGE("%c index=%zu, name=%s, layerStack=%d, z=%d, visible=%d, flags=%x, alpha=%x",
+            ALOGE("%c index=%zu, name=%s, layerStack=%d, z=%d, visible=%d, flags=%x, alpha=%.3f",
                     visible ? '+' : '-',
                             i, layer->getName().string(), state.layerStack, state.z,
                             layer->isVisible(), state.flags, state.alpha);