diff --git a/libs/renderengine/gl/GLESRenderEngine.cpp b/libs/renderengine/gl/GLESRenderEngine.cpp
index c5a9942..c137394 100644
--- a/libs/renderengine/gl/GLESRenderEngine.cpp
+++ b/libs/renderengine/gl/GLESRenderEngine.cpp
@@ -449,6 +449,7 @@
 }
 
 base::unique_fd GLESRenderEngine::flush() {
+    ATRACE_CALL();
     if (!GLExtensions::getInstance().hasNativeFenceSync()) {
         return base::unique_fd();
     }
@@ -479,6 +480,7 @@
 }
 
 bool GLESRenderEngine::finish() {
+    ATRACE_CALL();
     if (!GLExtensions::getInstance().hasFenceSync()) {
         ALOGW("no synchronization support");
         return false;
@@ -594,6 +596,7 @@
 }
 
 void GLESRenderEngine::bindExternalTextureImage(uint32_t texName, const Image& image) {
+    ATRACE_CALL();
     const GLImage& glImage = static_cast<const GLImage&>(image);
     const GLenum target = GL_TEXTURE_EXTERNAL_OES;
 
@@ -608,8 +611,15 @@
 }
 
 status_t GLESRenderEngine::bindExternalTextureBuffer(uint32_t texName, sp<GraphicBuffer> buffer,
+                                                     sp<Fence> bufferFence, bool readCache) {
+    return bindExternalTextureBuffer(texName, buffer, bufferFence, readCache,
+                                     /*persistCache=*/false);
+}
+
+status_t GLESRenderEngine::bindExternalTextureBuffer(uint32_t texName, sp<GraphicBuffer> buffer,
                                                      sp<Fence> bufferFence, bool readCache,
                                                      bool persistCache) {
+    ATRACE_CALL();
     if (readCache) {
         auto cachedImage = mImageCache.find(buffer->getId());
 
@@ -655,7 +665,7 @@
     }
 
     // We don't always want to persist to the cache, e.g. on older devices we
-    // might bind for synchronization purpoeses, but that might leak if we never
+    // might bind for synchronization purposes, but that might leak if we never
     // call drawLayers again, so it's just better to recreate the image again
     // if needed when we draw.
     if (persistCache) {
@@ -703,6 +713,7 @@
 }
 
 status_t GLESRenderEngine::bindFrameBuffer(Framebuffer* framebuffer) {
+    ATRACE_CALL();
     GLFramebuffer* glFramebuffer = static_cast<GLFramebuffer*>(framebuffer);
     EGLImageKHR eglImage = glFramebuffer->getEGLImage();
     uint32_t textureName = glFramebuffer->getTextureName();
@@ -770,6 +781,7 @@
                                       const std::vector<LayerSettings>& layers,
                                       ANativeWindowBuffer* const buffer,
                                       base::unique_fd* drawFence) {
+    ATRACE_CALL();
     if (layers.empty()) {
         ALOGV("Drawing empty layer stack");
         return NO_ERROR;
@@ -786,6 +798,13 @@
 
     evictImages(layers);
 
+    // clear the entire buffer, sometimes when we reuse buffers we'd persist
+    // ghost images otherwise.
+    // we also require a full transparent framebuffer for overlays. This is
+    // probably not quite efficient on all GPUs, since we could filter out
+    // opaque layers.
+    clearWithColor(0.0, 0.0, 0.0, 0.0);
+
     setViewportAndProjection(display.physicalDisplay, display.clip);
 
     setOutputDataSpace(display.outputDataspace);
@@ -794,6 +813,7 @@
     mat4 projectionMatrix = mState.projectionMatrix * display.globalTransform;
     mState.projectionMatrix = projectionMatrix;
     if (!display.clearRegion.isEmpty()) {
+        glDisable(GL_BLEND);
         fillRegionWithColor(display.clearRegion, 0.0, 0.0, 0.0, 1.0);
     }
 
@@ -813,9 +833,11 @@
 
         bool usePremultipliedAlpha = true;
         bool disableTexture = true;
+        bool isOpaque = false;
 
         if (layer.source.buffer.buffer != nullptr) {
             disableTexture = false;
+            isOpaque = layer.source.buffer.isOpaque;
 
             sp<GraphicBuffer> gBuf = layer.source.buffer.buffer;
 
@@ -825,17 +847,19 @@
 
             usePremultipliedAlpha = layer.source.buffer.usePremultipliedAlpha;
             Texture texture(Texture::TEXTURE_EXTERNAL, layer.source.buffer.textureName);
-            texture.setMatrix(layer.source.buffer.textureTransform.asArray());
+            mat4 texMatrix = layer.source.buffer.textureTransform;
+
+            texture.setMatrix(texMatrix.asArray());
             texture.setFiltering(layer.source.buffer.useTextureFiltering);
 
             texture.setDimensions(gBuf->getWidth(), gBuf->getHeight());
             setSourceY410BT2020(layer.source.buffer.isY410BT2020);
 
             renderengine::Mesh::VertexArray<vec2> texCoords(mesh.getTexCoordArray<vec2>());
-            texCoords[0] = vec2(0.0, 1.0);
-            texCoords[1] = vec2(0.0, 0.0);
-            texCoords[2] = vec2(1.0, 0.0);
-            texCoords[3] = vec2(1.0, 1.0);
+            texCoords[0] = vec2(0.0, 0.0);
+            texCoords[1] = vec2(0.0, 1.0);
+            texCoords[2] = vec2(1.0, 1.0);
+            texCoords[3] = vec2(1.0, 0.0);
             setupLayerTexturing(texture);
         }
 
@@ -843,8 +867,11 @@
         const half4 color = half4(solidColor.r, solidColor.g, solidColor.b, layer.alpha);
         // Buffer sources will have a black solid color ignored in the shader,
         // so in that scenario the solid color passed here is arbitrary.
-        setupLayerBlending(usePremultipliedAlpha, layer.source.buffer.isOpaque, disableTexture,
-                           color, layer.geometry.roundedCornersRadius);
+        setupLayerBlending(usePremultipliedAlpha, isOpaque, disableTexture, color,
+                           layer.geometry.roundedCornersRadius);
+        if (layer.disableBlending) {
+            glDisable(GL_BLEND);
+        }
         setSourceDataSpace(layer.sourceDataspace);
 
         drawMesh(mesh);
@@ -903,6 +930,7 @@
 }
 
 void GLESRenderEngine::setViewportAndProjection(Rect viewport, Rect clip) {
+    ATRACE_CALL();
     mVpWidth = viewport.getWidth();
     mVpHeight = viewport.getHeight();
 
diff --git a/libs/renderengine/gl/GLESRenderEngine.h b/libs/renderengine/gl/GLESRenderEngine.h
index e094860..34187f1 100644
--- a/libs/renderengine/gl/GLESRenderEngine.h
+++ b/libs/renderengine/gl/GLESRenderEngine.h
@@ -71,6 +71,8 @@
     void genTextures(size_t count, uint32_t* names) override;
     void deleteTextures(size_t count, uint32_t const* names) override;
     void bindExternalTextureImage(uint32_t texName, const Image& image) override;
+    status_t bindExternalTextureBuffer(uint32_t texName, sp<GraphicBuffer> buffer, sp<Fence> fence,
+                                       bool readCache);
     status_t bindFrameBuffer(Framebuffer* framebuffer) override;
     void unbindFrameBuffer(Framebuffer* framebuffer) override;
     void checkErrors() const override;
@@ -184,6 +186,9 @@
     const bool mUseColorManagement = false;
 
     // Cache of GL images that we'll store per GraphicBuffer ID
+    // TODO: Layer should call back on destruction instead to clean this up,
+    // as it has better system utilization at the potential expense of a
+    // more complicated interface.
     std::unordered_map<uint64_t, std::unique_ptr<Image>> mImageCache;
 
     class FlushTracer {
diff --git a/libs/renderengine/gl/GLFramebuffer.cpp b/libs/renderengine/gl/GLFramebuffer.cpp
index 4a519bb..0e3b405 100644
--- a/libs/renderengine/gl/GLFramebuffer.cpp
+++ b/libs/renderengine/gl/GLFramebuffer.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
 #include "GLFramebuffer.h"
 
 #include <GLES/gl.h>
@@ -21,6 +23,7 @@
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <nativebase/nativebase.h>
+#include <utils/Trace.h>
 #include "GLESRenderEngine.h"
 
 namespace android {
@@ -40,6 +43,7 @@
 }
 
 bool GLFramebuffer::setNativeWindowBuffer(ANativeWindowBuffer* nativeBuffer, bool isProtected) {
+    ATRACE_CALL();
     if (mEGLImage != EGL_NO_IMAGE_KHR) {
         eglDestroyImageKHR(mEGLDisplay, mEGLImage);
         mEGLImage = EGL_NO_IMAGE_KHR;
diff --git a/libs/renderengine/gl/GLImage.cpp b/libs/renderengine/gl/GLImage.cpp
index 587cb31..77e648e 100644
--- a/libs/renderengine/gl/GLImage.cpp
+++ b/libs/renderengine/gl/GLImage.cpp
@@ -14,11 +14,14 @@
  * limitations under the License.
  */
 
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
 #include "GLImage.h"
 
 #include <vector>
 
 #include <log/log.h>
+#include <utils/Trace.h>
 #include "GLESRenderEngine.h"
 #include "GLExtensions.h"
 
@@ -50,6 +53,7 @@
 }
 
 bool GLImage::setNativeWindowBuffer(ANativeWindowBuffer* buffer, bool isProtected) {
+    ATRACE_CALL();
     if (mEGLImage != EGL_NO_IMAGE_KHR) {
         if (!eglDestroyImageKHR(mEGLDisplay, mEGLImage)) {
             ALOGE("failed to destroy image: %#x", eglGetError());
diff --git a/libs/renderengine/include/renderengine/LayerSettings.h b/libs/renderengine/include/renderengine/LayerSettings.h
index 56ac714..aa45ed8 100644
--- a/libs/renderengine/include/renderengine/LayerSettings.h
+++ b/libs/renderengine/include/renderengine/LayerSettings.h
@@ -126,6 +126,9 @@
     // Additional layer-specific color transform to be applied before the global
     // transform.
     mat4 colorTransform = mat4();
+
+    // True if blending will be forced to be disabled.
+    bool disableBlending = false;
 };
 
 } // namespace renderengine
diff --git a/libs/renderengine/include/renderengine/RenderEngine.h b/libs/renderengine/include/renderengine/RenderEngine.h
index 20dd996..bc1a4da 100644
--- a/libs/renderengine/include/renderengine/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/RenderEngine.h
@@ -108,6 +108,8 @@
     virtual void genTextures(size_t count, uint32_t* names) = 0;
     virtual void deleteTextures(size_t count, uint32_t const* names) = 0;
     virtual void bindExternalTextureImage(uint32_t texName, const Image& image) = 0;
+    virtual status_t bindExternalTextureBuffer(uint32_t texName, sp<GraphicBuffer> buffer,
+                                               sp<Fence> fence, bool cleanCache) = 0;
     // When binding a native buffer, it must be done before setViewportAndProjection
     // Returns NO_ERROR when binds successfully, NO_MEMORY when there's no memory for allocation.
     virtual status_t bindFrameBuffer(Framebuffer* framebuffer) = 0;
diff --git a/libs/renderengine/include/renderengine/mock/RenderEngine.h b/libs/renderengine/include/renderengine/mock/RenderEngine.h
index b4c7c96..4b86cfe 100644
--- a/libs/renderengine/include/renderengine/mock/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/mock/RenderEngine.h
@@ -52,6 +52,7 @@
     MOCK_METHOD2(genTextures, void(size_t, uint32_t*));
     MOCK_METHOD2(deleteTextures, void(size_t, uint32_t const*));
     MOCK_METHOD2(bindExternalTextureImage, void(uint32_t, const renderengine::Image&));
+    MOCK_METHOD4(bindExternalTextureBuffer, status_t(uint32_t, sp<GraphicBuffer>, sp<Fence>, bool));
     MOCK_CONST_METHOD0(checkErrors, void());
     MOCK_METHOD4(setViewportAndProjection,
                  void(size_t, size_t, Rect, ui::Transform::orientation_flags));
diff --git a/libs/renderengine/tests/RenderEngineTest.cpp b/libs/renderengine/tests/RenderEngineTest.cpp
index bef25a8..0ee6153 100644
--- a/libs/renderengine/tests/RenderEngineTest.cpp
+++ b/libs/renderengine/tests/RenderEngineTest.cpp
@@ -194,7 +194,7 @@
 
     void clearLeftRegion();
 
-    void fillBufferThenClearRegion();
+    void clearRegion();
 
     // Dumb hack to get aroud the fact that tear-down for renderengine isn't
     // well defined right now, so we can't create multiple instances
@@ -685,14 +685,13 @@
     invokeDraw(settings, layers, mBuffer);
 }
 
-void RenderEngineTest::fillBufferThenClearRegion() {
-    fillGreenBuffer<ColorSourceVariant>();
+void RenderEngineTest::clearRegion() {
     // Reuse mBuffer
     clearLeftRegion();
     expectBufferColor(Rect(DEFAULT_DISPLAY_WIDTH / 2, DEFAULT_DISPLAY_HEIGHT), 0, 0, 0, 255);
     expectBufferColor(Rect(DEFAULT_DISPLAY_WIDTH / 2, 0, DEFAULT_DISPLAY_WIDTH,
                            DEFAULT_DISPLAY_HEIGHT),
-                      0, 255, 0, 255);
+                      0, 0, 0, 0);
 }
 
 TEST_F(RenderEngineTest, drawLayers_noLayersToDraw) {
@@ -855,8 +854,8 @@
     fillBufferWithoutPremultiplyAlpha();
 }
 
-TEST_F(RenderEngineTest, drawLayers_fillBufferThenClearRegion) {
-    fillBufferThenClearRegion();
+TEST_F(RenderEngineTest, drawLayers_clearRegion) {
+    clearRegion();
 }
 
 } // namespace android