diff --git a/libs/gui/BitTube.cpp b/libs/gui/BitTube.cpp
index ef7a6f5..351af65 100644
--- a/libs/gui/BitTube.cpp
+++ b/libs/gui/BitTube.cpp
@@ -86,6 +86,10 @@
     mReceiveFd = std::move(receiveFd);
 }
 
+void BitTube::setSendFd(base::unique_fd&& sendFd) {
+    mSendFd = std::move(sendFd);
+}
+
 ssize_t BitTube::write(void const* vaddr, size_t size) {
     ssize_t err, len;
     do {
@@ -115,6 +119,11 @@
 
     status_t result = reply->writeDupFileDescriptor(mReceiveFd);
     mReceiveFd.reset();
+    if (result != NO_ERROR) {
+        return result;
+    }
+    result = reply->writeDupFileDescriptor(mSendFd);
+    mSendFd.reset();
     return result;
 }
 
@@ -126,6 +135,13 @@
         ALOGE("BitTube::readFromParcel: can't dup file descriptor (%s)", strerror(error));
         return -error;
     }
+    mSendFd.reset(dup(parcel->readFileDescriptor()));
+    if (mSendFd < 0) {
+        mSendFd.reset();
+        int error = errno;
+        ALOGE("BitTube::readFromParcel: can't dup file descriptor (%s)", strerror(error));
+        return -error;
+    }
     return NO_ERROR;
 }
 
diff --git a/libs/gui/DisplayEventDispatcher.cpp b/libs/gui/DisplayEventDispatcher.cpp
index b33bc9e..682fe91 100644
--- a/libs/gui/DisplayEventDispatcher.cpp
+++ b/libs/gui/DisplayEventDispatcher.cpp
@@ -89,12 +89,8 @@
     return OK;
 }
 
-void DisplayEventDispatcher::requestLatestConfig() {
-    status_t status = mReceiver.requestLatestConfig();
-    if (status) {
-        ALOGW("Failed enable config events, status=%d", status);
-        return;
-    }
+void DisplayEventDispatcher::injectEvent(const DisplayEventReceiver::Event& event) {
+    mReceiver.sendEvents(&event, 1);
 }
 
 int DisplayEventDispatcher::getFd() const {
@@ -157,6 +153,9 @@
                     dispatchConfigChanged(ev.header.timestamp, ev.header.displayId,
                                           ev.config.configId, ev.config.vsyncPeriod);
                     break;
+                case DisplayEventReceiver::DISPLAY_EVENT_NULL:
+                    dispatchNullEvent(ev.header.timestamp, ev.header.displayId);
+                    break;
                 default:
                     ALOGW("dispatcher %p ~ ignoring unknown event type %#x", this, ev.header.type);
                     break;
@@ -168,4 +167,5 @@
     }
     return gotVsync;
 }
+
 } // namespace android
diff --git a/libs/gui/DisplayEventReceiver.cpp b/libs/gui/DisplayEventReceiver.cpp
index 1fed509..f2b0962 100644
--- a/libs/gui/DisplayEventReceiver.cpp
+++ b/libs/gui/DisplayEventReceiver.cpp
@@ -79,14 +79,6 @@
     return NO_INIT;
 }
 
-status_t DisplayEventReceiver::requestLatestConfig() {
-    if (mEventConnection != nullptr) {
-        mEventConnection->requestLatestConfig();
-        return NO_ERROR;
-    }
-    return NO_INIT;
-}
-
 ssize_t DisplayEventReceiver::getEvents(DisplayEventReceiver::Event* events,
         size_t count) {
     return DisplayEventReceiver::getEvents(mDataChannel.get(), events, count);
@@ -98,6 +90,10 @@
     return gui::BitTube::recvObjects(dataChannel, events, count);
 }
 
+ssize_t DisplayEventReceiver::sendEvents(Event const* events, size_t count) {
+    return DisplayEventReceiver::sendEvents(mDataChannel.get(), events, count);
+}
+
 ssize_t DisplayEventReceiver::sendEvents(gui::BitTube* dataChannel,
         Event const* events, size_t count)
 {
diff --git a/libs/gui/IDisplayEventConnection.cpp b/libs/gui/IDisplayEventConnection.cpp
index aa74bfd..c0e246f 100644
--- a/libs/gui/IDisplayEventConnection.cpp
+++ b/libs/gui/IDisplayEventConnection.cpp
@@ -26,8 +26,7 @@
     STEAL_RECEIVE_CHANNEL = IBinder::FIRST_CALL_TRANSACTION,
     SET_VSYNC_RATE,
     REQUEST_NEXT_VSYNC,
-    REQUEST_LATEST_CONFIG,
-    LAST = REQUEST_LATEST_CONFIG,
+    LAST = REQUEST_NEXT_VSYNC,
 };
 
 } // Anonymous namespace
@@ -54,11 +53,6 @@
         callRemoteAsync<decltype(&IDisplayEventConnection::requestNextVsync)>(
                 Tag::REQUEST_NEXT_VSYNC);
     }
-
-    void requestLatestConfig() override {
-        callRemoteAsync<decltype(&IDisplayEventConnection::requestLatestConfig)>(
-                Tag::REQUEST_LATEST_CONFIG);
-    }
 };
 
 // Out-of-line virtual method definition to trigger vtable emission in this translation unit (see
@@ -80,8 +74,6 @@
             return callLocal(data, reply, &IDisplayEventConnection::setVsyncRate);
         case Tag::REQUEST_NEXT_VSYNC:
             return callLocalAsync(data, reply, &IDisplayEventConnection::requestNextVsync);
-        case Tag::REQUEST_LATEST_CONFIG:
-            return callLocalAsync(data, reply, &IDisplayEventConnection::requestLatestConfig);
     }
 }
 
diff --git a/libs/gui/include/gui/DisplayEventDispatcher.h b/libs/gui/include/gui/DisplayEventDispatcher.h
index f210c34..eb5b004 100644
--- a/libs/gui/include/gui/DisplayEventDispatcher.h
+++ b/libs/gui/include/gui/DisplayEventDispatcher.h
@@ -31,7 +31,7 @@
     status_t initialize();
     void dispose();
     status_t scheduleVsync();
-    void requestLatestConfig();
+    void injectEvent(const DisplayEventReceiver::Event& event);
     int getFd() const;
     virtual int handleEvent(int receiveFd, int events, void* data);
 
@@ -48,6 +48,9 @@
                                  bool connected) = 0;
     virtual void dispatchConfigChanged(nsecs_t timestamp, PhysicalDisplayId displayId,
                                        int32_t configId, nsecs_t vsyncPeriod) = 0;
+    // AChoreographer-specific hook for processing null-events so that looper
+    // can be properly poked.
+    virtual void dispatchNullEvent(nsecs_t timestamp, PhysicalDisplayId displayId) = 0;
 
     bool processPendingEvents(nsecs_t* outTimestamp, PhysicalDisplayId* outDisplayId,
                               uint32_t* outCount);
diff --git a/libs/gui/include/gui/DisplayEventReceiver.h b/libs/gui/include/gui/DisplayEventReceiver.h
index 8d49184..0e10d1a 100644
--- a/libs/gui/include/gui/DisplayEventReceiver.h
+++ b/libs/gui/include/gui/DisplayEventReceiver.h
@@ -53,6 +53,7 @@
         DISPLAY_EVENT_VSYNC = fourcc('v', 's', 'y', 'n'),
         DISPLAY_EVENT_HOTPLUG = fourcc('p', 'l', 'u', 'g'),
         DISPLAY_EVENT_CONFIG_CHANGED = fourcc('c', 'o', 'n', 'f'),
+        DISPLAY_EVENT_NULL = fourcc('n', 'u', 'l', 'l'),
     };
 
     struct Event {
@@ -130,6 +131,7 @@
      * sendEvents write events to the queue and returns how many events were
      * written.
      */
+    ssize_t sendEvents(Event const* events, size_t count);
     static ssize_t sendEvents(gui::BitTube* dataChannel, Event const* events, size_t count);
 
     /*
@@ -146,12 +148,6 @@
      */
     status_t requestNextVsync();
 
-    /*
-     * requestLatestConfig() force-requests the current config for the primary
-     * display.
-     */
-    status_t requestLatestConfig();
-
 private:
     sp<IDisplayEventConnection> mEventConnection;
     std::unique_ptr<gui::BitTube> mDataChannel;
diff --git a/libs/gui/include/gui/IDisplayEventConnection.h b/libs/gui/include/gui/IDisplayEventConnection.h
index 674aafd..cff22a3 100644
--- a/libs/gui/include/gui/IDisplayEventConnection.h
+++ b/libs/gui/include/gui/IDisplayEventConnection.h
@@ -51,11 +51,6 @@
      * requestNextVsync() schedules the next vsync event. It has no effect if the vsync rate is > 0.
      */
     virtual void requestNextVsync() = 0; // Asynchronous
-
-    /*
-     * requestLatestConfig() requests the config for the primary display.
-     */
-    virtual void requestLatestConfig() = 0; // Asynchronous
 };
 
 class BnDisplayEventConnection : public SafeBnInterface<IDisplayEventConnection> {
diff --git a/libs/gui/include/private/gui/BitTube.h b/libs/gui/include/private/gui/BitTube.h
index 13c0162..8048518 100644
--- a/libs/gui/include/private/gui/BitTube.h
+++ b/libs/gui/include/private/gui/BitTube.h
@@ -58,6 +58,9 @@
     // resets this BitTube's receive file descriptor to receiveFd
     void setReceiveFd(base::unique_fd&& receiveFd);
 
+    // resets this BitTube's send file descriptor to sendFd
+    void setSendFd(base::unique_fd&& sendFd);
+
     // send objects (sized blobs). All objects are guaranteed to be written or the call fails.
     template <typename T>
     static ssize_t sendObjects(BitTube* tube, T const* events, size_t count) {
@@ -85,7 +88,7 @@
     // the message, excess data is silently discarded.
     ssize_t read(void* vaddr, size_t size);
 
-    base::unique_fd mSendFd;
+    mutable base::unique_fd mSendFd;
     mutable base::unique_fd mReceiveFd;
 
     static ssize_t sendObjects(BitTube* tube, void const* events, size_t count, size_t objSize);