diff --git a/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp b/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp
index 31db31f..25e351c 100644
--- a/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp
+++ b/libs/surfaceflinger/DisplayHardware/DisplayHardware.cpp
@@ -183,9 +183,11 @@
     LOGI("extensions: %s", egl_extensions);
     LOGI("Client API: %s", eglQueryString(display, EGL_CLIENT_APIS)?:"Not Supported");
 
-    // TODO: get the real "update_on_demand" behavior (probably should be HAL module)
-    // FIXME: mFlags |= UPDATE_ON_DEMAND;
 
+    if (mNativeWindow->isUpdateOnDemand()) {
+        mFlags |= UPDATE_ON_DEMAND;
+    }
+    
     if (eglGetConfigAttrib(display, config, EGL_CONFIG_CAVEAT, &dummy) == EGL_TRUE) {
         if (dummy == EGL_SLOW_CONFIG)
             mFlags |= SLOW_CONFIG;
@@ -210,7 +212,7 @@
 
     mDpiX = mNativeWindow->xdpi;
     mDpiX = mNativeWindow->ydpi;
-    mRefreshRate = mNativeWindow->getDevice()->fps; 
+    mRefreshRate = fbDev->fps; 
     
     char property[PROPERTY_VALUE_MAX];
     if (property_get("ro.sf.lcd_density", property, NULL) <= 0) {
@@ -314,6 +316,10 @@
                 b.left, b.top, b.width(), b.height());
     } 
 
+    if (mFlags & UPDATE_ON_DEMAND) {
+        mNativeWindow->setUpdateRectangle(dirty.bounds());
+    }
+    
     mPageFlipCount++;
     eglSwapBuffers(dpy, surface);
     checkEGLErrors("eglSwapBuffers");
diff --git a/libs/ui/FramebufferNativeWindow.cpp b/libs/ui/FramebufferNativeWindow.cpp
index 83b333f..8c8fd6b 100644
--- a/libs/ui/FramebufferNativeWindow.cpp
+++ b/libs/ui/FramebufferNativeWindow.cpp
@@ -76,7 +76,7 @@
  */
 
 FramebufferNativeWindow::FramebufferNativeWindow() 
-    : BASE(), fbDev(0), grDev(0)
+    : BASE(), fbDev(0), grDev(0), mUpdateOnDemand(false)
 {
     hw_module_t const* module;
     if (hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module) == 0) {
@@ -86,6 +86,8 @@
         int err;
 
         
+        mUpdateOnDemand = (fbDev->setUpdateRect != 0);
+        
         // initialize the buffer FIFO
         mNumBuffers = 2;
         mNumFreeBuffers = 2;
@@ -131,6 +133,14 @@
     framebuffer_close(fbDev);
 }
 
+status_t FramebufferNativeWindow::setUpdateRectangle(const Rect& r) 
+{
+    if (!mUpdateOnDemand) {
+        return INVALID_OPERATION;
+    }
+    return fbDev->setUpdateRect(fbDev, r.left, r.top, r.width(), r.height());
+}
+
 int FramebufferNativeWindow::setSwapInterval(
         android_native_window_t* window, int interval) 
 {