Merge "Export libui_headers as vndk header only library" into oc-mr1-dev am: 0d70e447b5
am: 5e11d48a1f

Change-Id: Ia0c6cc4eddd55f7524cba5c5d46bbde9d635f1bb
diff --git a/cmds/installd/tests/Android.bp b/cmds/installd/tests/Android.bp
index 630c1f3..443dce6 100644
--- a/cmds/installd/tests/Android.bp
+++ b/cmds/installd/tests/Android.bp
@@ -5,13 +5,13 @@
     srcs: ["installd_utils_test.cpp"],
     shared_libs: [
         "libbase",
-        "liblog",
         "libutils",
         "libcutils",
     ],
     static_libs: [
-        "libinstalld",
         "libdiskusage",
+        "libinstalld",
+        "liblog",
     ],
 }
 
@@ -23,14 +23,14 @@
         "libbase",
         "libbinder",
         "libcutils",
-        "liblog",
-        "liblogwrap",
         "libselinux",
         "libutils",
     ],
     static_libs: [
-        "libinstalld",
         "libdiskusage",
+        "libinstalld",
+        "liblog",
+        "liblogwrap",
     ],
 }
 
@@ -42,13 +42,13 @@
         "libbase",
         "libbinder",
         "libcutils",
-        "liblog",
-        "liblogwrap",
         "libselinux",
         "libutils",
     ],
     static_libs: [
-        "libinstalld",
         "libdiskusage",
+        "libinstalld",
+        "liblog",
+        "liblogwrap",
     ],
 }
diff --git a/include/android/sensor.h b/include/android/sensor.h
index a88733c..2db0ee7 100644
--- a/include/android/sensor.h
+++ b/include/android/sensor.h
@@ -197,7 +197,7 @@
  * A sensor event.
  */
 
-/* NOTE: Must match hardware/sensors.h */
+/* NOTE: changes to these structs have to be backward compatible */
 typedef struct ASensorVector {
     union {
         float v[3];
@@ -259,7 +259,7 @@
     };
 } AAdditionalInfoEvent;
 
-/* NOTE: Must match hardware/sensors.h */
+/* NOTE: changes to this struct has to be backward compatible */
 typedef struct ASensorEvent {
     int32_t version; /* sizeof(struct ASensorEvent) */
     int32_t sensor;
diff --git a/include/input/VelocityTracker.h b/include/input/VelocityTracker.h
index 795f575..ffa1614 100644
--- a/include/input/VelocityTracker.h
+++ b/include/input/VelocityTracker.h
@@ -264,6 +264,40 @@
     Movement mMovements[HISTORY_SIZE];
 };
 
+class ImpulseVelocityTrackerStrategy : public VelocityTrackerStrategy {
+public:
+    ImpulseVelocityTrackerStrategy();
+    virtual ~ImpulseVelocityTrackerStrategy();
+
+    virtual void clear();
+    virtual void clearPointers(BitSet32 idBits);
+    virtual void addMovement(nsecs_t eventTime, BitSet32 idBits,
+            const VelocityTracker::Position* positions);
+    virtual bool getEstimator(uint32_t id, VelocityTracker::Estimator* outEstimator) const;
+
+private:
+    // Sample horizon.
+    // We don't use too much history by default since we want to react to quick
+    // changes in direction.
+    static constexpr nsecs_t HORIZON = 100 * 1000000; // 100 ms
+
+    // Number of samples to keep.
+    static constexpr size_t HISTORY_SIZE = 20;
+
+    struct Movement {
+        nsecs_t eventTime;
+        BitSet32 idBits;
+        VelocityTracker::Position positions[MAX_POINTERS];
+
+        inline const VelocityTracker::Position& getPosition(uint32_t id) const {
+            return positions[idBits.getIndexOfBit(id)];
+        }
+    };
+
+    size_t mIndex;
+    Movement mMovements[HISTORY_SIZE];
+};
+
 } // namespace android
 
 #endif // _LIBINPUT_VELOCITY_TRACKER_H
diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 9b06e63..573f685 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -45,6 +45,8 @@
     output.writeInt32(overrideScalingMode);
     output.writeStrongBinder(IInterface::asBinder(barrierGbp));
     output.writeStrongBinder(relativeLayerHandle);
+    output.writeStrongBinder(parentHandleForChild);
+    output.writeStrongBinder(childHandle);
     output.write(transparentRegion);
     return NO_ERROR;
 }
@@ -77,6 +79,8 @@
     barrierGbp =
         interface_cast<IGraphicBufferProducer>(input.readStrongBinder());
     relativeLayerHandle = input.readStrongBinder();
+    parentHandleForChild = input.readStrongBinder();
+    childHandle = input.readStrongBinder();
     input.read(transparentRegion);
     return NO_ERROR;
 }
diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 5b1c599..6c9d88b 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -1509,6 +1509,12 @@
     return NO_ERROR;
 }
 
+android_dataspace_t Surface::getBuffersDataSpace() {
+    ALOGV("Surface::getBuffersDataSpace");
+    Mutex::Autolock lock(mMutex);
+    return mDataSpace;
+}
+
 void Surface::freeAllBuffers() {
     for (int i = 0; i < NUM_BUFFER_SLOTS; i++) {
         mSlots[i].buffer = 0;
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 7ae2672..b0ae7e0 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -176,6 +176,9 @@
     status_t reparentChildren(const sp<SurfaceComposerClient>& client,
             const sp<IBinder>& id,
             const sp<IBinder>& newParentHandle);
+    status_t reparentChild(const sp<SurfaceComposerClient>& client,
+            const sp<IBinder>& id, const sp<IBinder>& newParentHandle,
+            const sp<IBinder>& childHandle);
     status_t detachChildren(const sp<SurfaceComposerClient>& client,
             const sp<IBinder>& id);
     status_t setOverrideScalingMode(const sp<SurfaceComposerClient>& client,
@@ -493,6 +496,21 @@
     return NO_ERROR;
 }
 
+status_t Composer::reparentChild(const sp<SurfaceComposerClient>& client,
+        const sp<IBinder>& id,
+        const sp<IBinder>& newParentHandle,
+        const sp<IBinder>& childHandle) {
+    Mutex::Autolock lock(mLock);
+    layer_state_t* s = getLayerStateLocked(client, id);
+    if (!s) {
+        return BAD_INDEX;
+    }
+    s->what |= layer_state_t::eReparentChild;
+    s->parentHandleForChild = newParentHandle;
+    s->childHandle = childHandle;
+    return NO_ERROR;
+}
+
 status_t Composer::detachChildren(
         const sp<SurfaceComposerClient>& client,
         const sp<IBinder>& id) {
@@ -831,6 +849,11 @@
     return getComposer().reparentChildren(this, id, newParentHandle);
 }
 
+status_t SurfaceComposerClient::reparentChild(const sp<IBinder>& id,
+        const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle) {
+    return getComposer().reparentChild(this, id, newParentHandle, childHandle);
+}
+
 status_t SurfaceComposerClient::detachChildren(const sp<IBinder>& id) {
     return getComposer().detachChildren(this, id);
 }
diff --git a/libs/gui/SurfaceControl.cpp b/libs/gui/SurfaceControl.cpp
index 58bd273..b9c5ef9 100644
--- a/libs/gui/SurfaceControl.cpp
+++ b/libs/gui/SurfaceControl.cpp
@@ -191,6 +191,13 @@
     return mClient->reparentChildren(mHandle, newParentHandle);
 }
 
+status_t SurfaceControl::reparentChild(const sp<IBinder>& newParentHandle,
+        const sp<IBinder>& childHandle) {
+    status_t err = validate();
+    if (err < 0) return err;
+    return mClient->reparentChild(mHandle, newParentHandle, childHandle);
+}
+
 status_t SurfaceControl::detachChildren() {
     status_t err = validate();
     if (err < 0) return err;
diff --git a/libs/gui/include/gui/Surface.h b/libs/gui/include/gui/Surface.h
index 55dd6bf..3fe29d9 100644
--- a/libs/gui/include/gui/Surface.h
+++ b/libs/gui/include/gui/Surface.h
@@ -281,6 +281,8 @@
     // detachNextBuffer, or attachBuffer call.
     status_t getAndFlushRemovedBuffers(std::vector<sp<GraphicBuffer>>* out);
 
+    android_dataspace_t getBuffersDataSpace();
+
 protected:
     enum { NUM_BUFFER_SLOTS = BufferQueueDefs::NUM_BUFFER_SLOTS };
     enum { DEFAULT_FORMAT = PIXEL_FORMAT_RGBA_8888 };
diff --git a/libs/gui/include/gui/SurfaceComposerClient.h b/libs/gui/include/gui/SurfaceComposerClient.h
index 145c059..6e2cb83 100644
--- a/libs/gui/include/gui/SurfaceComposerClient.h
+++ b/libs/gui/include/gui/SurfaceComposerClient.h
@@ -161,6 +161,8 @@
             const sp<Surface>& handle, uint64_t frameNumber);
     status_t    reparentChildren(const sp<IBinder>& id,
             const sp<IBinder>& newParentHandle);
+    status_t    reparentChild(const sp<IBinder>& id, const sp<IBinder>& newParentHandle,
+            const sp<IBinder>& childHandle);
     status_t    detachChildren(const sp<IBinder>& id);
     status_t    setOverrideScalingMode(const sp<IBinder>& id,
             int32_t overrideScalingMode);
diff --git a/libs/gui/include/gui/SurfaceControl.h b/libs/gui/include/gui/SurfaceControl.h
index c15209d..d8b67ef 100644
--- a/libs/gui/include/gui/SurfaceControl.h
+++ b/libs/gui/include/gui/SurfaceControl.h
@@ -124,6 +124,12 @@
     // Reparents all children of this layer to the new parent handle.
     status_t reparentChildren(const sp<IBinder>& newParentHandle);
 
+    // Reparents a specified child from this layer to the new parent handle.
+    // The child, parent, and new parent must all have the same client.
+    // This can be used instead of reparentChildren if the caller wants to
+    // only re-parent specific children.
+    status_t reparentChild(const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle);
+
     // Detaches all child surfaces (and their children recursively)
     // from their SurfaceControl.
     // The child SurfaceControl's will not throw exceptions or return errors,
diff --git a/libs/gui/include/private/gui/LayerState.h b/libs/gui/include/private/gui/LayerState.h
index 307c764..4f73e04 100644
--- a/libs/gui/include/private/gui/LayerState.h
+++ b/libs/gui/include/private/gui/LayerState.h
@@ -59,7 +59,8 @@
         eGeometryAppliesWithResize  = 0x00001000,
         eReparentChildren           = 0x00002000,
         eDetachChildren             = 0x00004000,
-        eRelativeLayerChanged       = 0x00008000
+        eRelativeLayerChanged       = 0x00008000,
+        eReparentChild              = 0x00010000
     };
 
     layer_state_t()
@@ -107,6 +108,9 @@
 
             sp<IBinder>     relativeLayerHandle;
 
+            sp<IBinder>     parentHandleForChild;
+            sp<IBinder>     childHandle;
+
             // non POD must be last. see write/read
             Region          transparentRegion;
 };
diff --git a/libs/input/VelocityTracker.cpp b/libs/input/VelocityTracker.cpp
index 62acea3..a914408 100644
--- a/libs/input/VelocityTracker.cpp
+++ b/libs/input/VelocityTracker.cpp
@@ -141,6 +141,11 @@
 }
 
 VelocityTrackerStrategy* VelocityTracker::createStrategy(const char* strategy) {
+    if (!strcmp("impulse", strategy)) {
+        // Physical model of pushing an object.  Quality: VERY GOOD.
+        // Works with duplicate coordinates, unclean finger liftoff.
+        return new ImpulseVelocityTrackerStrategy();
+    }
     if (!strcmp("lsq1", strategy)) {
         // 1st order least squares.  Quality: POOR.
         // Frequently underfits the touch data especially when the finger accelerates
@@ -352,9 +357,6 @@
 
 // --- LeastSquaresVelocityTrackerStrategy ---
 
-const nsecs_t LeastSquaresVelocityTrackerStrategy::HORIZON;
-const uint32_t LeastSquaresVelocityTrackerStrategy::HISTORY_SIZE;
-
 LeastSquaresVelocityTrackerStrategy::LeastSquaresVelocityTrackerStrategy(
         uint32_t degree, Weighting weighting) :
         mDegree(degree), mWeighting(weighting) {
@@ -863,10 +865,6 @@
 
 // --- LegacyVelocityTrackerStrategy ---
 
-const nsecs_t LegacyVelocityTrackerStrategy::HORIZON;
-const uint32_t LegacyVelocityTrackerStrategy::HISTORY_SIZE;
-const nsecs_t LegacyVelocityTrackerStrategy::MIN_DURATION;
-
 LegacyVelocityTrackerStrategy::LegacyVelocityTrackerStrategy() {
     clear();
 }
@@ -979,4 +977,192 @@
     return true;
 }
 
+// --- ImpulseVelocityTrackerStrategy ---
+
+ImpulseVelocityTrackerStrategy::ImpulseVelocityTrackerStrategy() {
+    clear();
+}
+
+ImpulseVelocityTrackerStrategy::~ImpulseVelocityTrackerStrategy() {
+}
+
+void ImpulseVelocityTrackerStrategy::clear() {
+    mIndex = 0;
+    mMovements[0].idBits.clear();
+}
+
+void ImpulseVelocityTrackerStrategy::clearPointers(BitSet32 idBits) {
+    BitSet32 remainingIdBits(mMovements[mIndex].idBits.value & ~idBits.value);
+    mMovements[mIndex].idBits = remainingIdBits;
+}
+
+void ImpulseVelocityTrackerStrategy::addMovement(nsecs_t eventTime, BitSet32 idBits,
+        const VelocityTracker::Position* positions) {
+    if (++mIndex == HISTORY_SIZE) {
+        mIndex = 0;
+    }
+
+    Movement& movement = mMovements[mIndex];
+    movement.eventTime = eventTime;
+    movement.idBits = idBits;
+    uint32_t count = idBits.count();
+    for (uint32_t i = 0; i < count; i++) {
+        movement.positions[i] = positions[i];
+    }
+}
+
+/**
+ * Calculate the total impulse provided to the screen and the resulting velocity.
+ *
+ * The touchscreen is modeled as a physical object.
+ * Initial condition is discussed below, but for now suppose that v(t=0) = 0
+ *
+ * The kinetic energy of the object at the release is E=0.5*m*v^2
+ * Then vfinal = sqrt(2E/m). The goal is to calculate E.
+ *
+ * The kinetic energy at the release is equal to the total work done on the object by the finger.
+ * The total work W is the sum of all dW along the path.
+ *
+ * dW = F*dx, where dx is the piece of path traveled.
+ * Force is change of momentum over time, F = dp/dt = m dv/dt.
+ * Then substituting:
+ * dW = m (dv/dt) * dx = m * v * dv
+ *
+ * Summing along the path, we get:
+ * W = sum(dW) = sum(m * v * dv) = m * sum(v * dv)
+ * Since the mass stays constant, the equation for final velocity is:
+ * vfinal = sqrt(2*sum(v * dv))
+ *
+ * Here,
+ * dv : change of velocity = (v[i+1]-v[i])
+ * dx : change of distance = (x[i+1]-x[i])
+ * dt : change of time = (t[i+1]-t[i])
+ * v : instantaneous velocity = dx/dt
+ *
+ * The final formula is:
+ * vfinal = sqrt(2) * sqrt(sum((v[i]-v[i-1])*|v[i]|)) for all i
+ * The absolute value is needed to properly account for the sign. If the velocity over a
+ * particular segment descreases, then this indicates braking, which means that negative
+ * work was done. So for two positive, but decreasing, velocities, this contribution would be
+ * negative and will cause a smaller final velocity.
+ *
+ * Initial condition
+ * There are two ways to deal with initial condition:
+ * 1) Assume that v(0) = 0, which would mean that the screen is initially at rest.
+ * This is not entirely accurate. We are only taking the past X ms of touch data, where X is
+ * currently equal to 100. However, a touch event that created a fling probably lasted for longer
+ * than that, which would mean that the user has already been interacting with the touchscreen
+ * and it has probably already been moving.
+ * 2) Assume that the touchscreen has already been moving at a certain velocity, calculate this
+ * initial velocity and the equivalent energy, and start with this initial energy.
+ * Consider an example where we have the following data, consisting of 3 points:
+ *                 time: t0, t1, t2
+ *                 x   : x0, x1, x2
+ *                 v   : 0 , v1, v2
+ * Here is what will happen in each of these scenarios:
+ * 1) By directly applying the formula above with the v(0) = 0 boundary condition, we will get
+ * vfinal = sqrt(2*(|v1|*(v1-v0) + |v2|*(v2-v1))). This can be simplified since v0=0
+ * vfinal = sqrt(2*(|v1|*v1 + |v2|*(v2-v1))) = sqrt(2*(v1^2 + |v2|*(v2 - v1)))
+ * since velocity is a real number
+ * 2) If we treat the screen as already moving, then it must already have an energy (per mass)
+ * equal to 1/2*v1^2. Then the initial energy should be 1/2*v1*2, and only the second segment
+ * will contribute to the total kinetic energy (since we can effectively consider that v0=v1).
+ * This will give the following expression for the final velocity:
+ * vfinal = sqrt(2*(1/2*v1^2 + |v2|*(v2-v1)))
+ * This analysis can be generalized to an arbitrary number of samples.
+ *
+ *
+ * Comparing the two equations above, we see that the only mathematical difference
+ * is the factor of 1/2 in front of the first velocity term.
+ * This boundary condition would allow for the "proper" calculation of the case when all of the
+ * samples are equally spaced in time and distance, which should suggest a constant velocity.
+ *
+ * Note that approach 2) is sensitive to the proper ordering of the data in time, since
+ * the boundary condition must be applied to the oldest sample to be accurate.
+ */
+static float calculateImpulseVelocity(const nsecs_t* t, const float* x, size_t count) {
+    // The input should be in reversed time order (most recent sample at index i=0)
+    // t[i] is in nanoseconds, but due to FP arithmetic, convert to seconds inside this function
+    static constexpr float NANOS_PER_SECOND = 1E-9;
+    static constexpr float sqrt2 = 1.41421356237;
+
+    if (count < 2) {
+        return 0; // if 0 or 1 points, velocity is zero
+    }
+    if (t[1] > t[0]) { // Algorithm will still work, but not perfectly
+        ALOGE("Samples provided to calculateImpulseVelocity in the wrong order");
+    }
+    if (count == 2) { // if 2 points, basic linear calculation
+        if (t[1] == t[0]) {
+            ALOGE("Events have identical time stamps t=%" PRId64 ", setting velocity = 0", t[0]);
+            return 0;
+        }
+        return (x[1] - x[0]) / (NANOS_PER_SECOND * (t[1] - t[0]));
+    }
+    // Guaranteed to have at least 3 points here
+    float work = 0;
+    float vprev, vcurr; // v[i-1] and v[i], respectively
+    vprev = 0;
+    for (size_t i = count - 1; i > 0 ; i--) { // start with the oldest sample and go forward in time
+        if (t[i] == t[i-1]) {
+            ALOGE("Events have identical time stamps t=%" PRId64 ", skipping sample", t[i]);
+            continue;
+        }
+        vcurr = (x[i] - x[i-1]) / (NANOS_PER_SECOND * (t[i] - t[i-1]));
+        work += (vcurr - vprev) * fabsf(vcurr);
+        if (i == count - 1) {
+            work *= 0.5; // initial condition, case 2) above
+        }
+        vprev = vcurr;
+    }
+    return (work < 0 ? -1.0 : 1.0) * sqrtf(fabsf(work)) * sqrt2;
+}
+
+bool ImpulseVelocityTrackerStrategy::getEstimator(uint32_t id,
+        VelocityTracker::Estimator* outEstimator) const {
+    outEstimator->clear();
+
+    // Iterate over movement samples in reverse time order and collect samples.
+    float x[HISTORY_SIZE];
+    float y[HISTORY_SIZE];
+    nsecs_t time[HISTORY_SIZE];
+    size_t m = 0; // number of points that will be used for fitting
+    size_t index = mIndex;
+    const Movement& newestMovement = mMovements[mIndex];
+    do {
+        const Movement& movement = mMovements[index];
+        if (!movement.idBits.hasBit(id)) {
+            break;
+        }
+
+        nsecs_t age = newestMovement.eventTime - movement.eventTime;
+        if (age > HORIZON) {
+            break;
+        }
+
+        const VelocityTracker::Position& position = movement.getPosition(id);
+        x[m] = position.x;
+        y[m] = position.y;
+        time[m] = movement.eventTime;
+        index = (index == 0 ? HISTORY_SIZE : index) - 1;
+    } while (++m < HISTORY_SIZE);
+
+    if (m == 0) {
+        return false; // no data
+    }
+    outEstimator->xCoeff[0] = 0;
+    outEstimator->yCoeff[0] = 0;
+    outEstimator->xCoeff[1] = calculateImpulseVelocity(time, x, m);
+    outEstimator->yCoeff[1] = calculateImpulseVelocity(time, y, m);
+    outEstimator->xCoeff[2] = 0;
+    outEstimator->yCoeff[2] = 0;
+    outEstimator->time = newestMovement.eventTime;
+    outEstimator->degree = 2; // similar results to 2nd degree fit
+    outEstimator->confidence = 1;
+#if DEBUG_STRATEGY
+    ALOGD("velocity: (%f, %f)", outEstimator->xCoeff[1], outEstimator->yCoeff[1]);
+#endif
+    return true;
+}
+
 } // namespace android
diff --git a/libs/sensor/OWNERS b/libs/sensor/OWNERS
new file mode 100644
index 0000000..6a38a1f
--- /dev/null
+++ b/libs/sensor/OWNERS
@@ -0,0 +1,2 @@
+ashutoshj@google.com
+pengxu@google.com
diff --git a/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp b/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
index f9f87ff..6b86433 100644
--- a/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
+++ b/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
@@ -429,7 +429,7 @@
       if (!status) {
         ALOGE(
             "ProducerQueue::FreeAllBuffers: Failed to remove buffer at "
-            "slot=%d.",
+            "slot=%zu.",
             slot);
         last_error = status.error_status();
       }
diff --git a/services/sensorservice/OWNERS b/services/sensorservice/OWNERS
new file mode 100644
index 0000000..6a38a1f
--- /dev/null
+++ b/services/sensorservice/OWNERS
@@ -0,0 +1,2 @@
+ashutoshj@google.com
+pengxu@google.com
diff --git a/services/sensorservice/SensorDevice.cpp b/services/sensorservice/SensorDevice.cpp
index 7d9b0b7..da3b275 100644
--- a/services/sensorservice/SensorDevice.cpp
+++ b/services/sensorservice/SensorDevice.cpp
@@ -223,8 +223,13 @@
 }
 
 void SensorDevice::autoDisable(void *ident, int handle) {
-    Info& info( mActivationCount.editValueFor(handle) );
     Mutex::Autolock _l(mLock);
+    ssize_t activationIndex = mActivationCount.indexOfKey(handle);
+    if (activationIndex < 0) {
+        ALOGW("Handle %d cannot be found in activation record", handle);
+        return;
+    }
+    Info& info(mActivationCount.editValueAt(activationIndex));
     info.removeBatchParamsForIdent(ident);
 }
 
@@ -235,7 +240,12 @@
     bool actuateHardware = false;
 
     Mutex::Autolock _l(mLock);
-    Info& info( mActivationCount.editValueFor(handle) );
+    ssize_t activationIndex = mActivationCount.indexOfKey(handle);
+    if (activationIndex < 0) {
+        ALOGW("Handle %d cannot be found in activation record", handle);
+        return BAD_VALUE;
+    }
+    Info& info(mActivationCount.editValueAt(activationIndex));
 
     ALOGD_IF(DEBUG_CONNECTIONS,
              "SensorDevice::activate: ident=%p, handle=0x%08x, enabled=%d, count=%zu",
@@ -329,7 +339,12 @@
              ident, handle, flags, samplingPeriodNs, maxBatchReportLatencyNs);
 
     Mutex::Autolock _l(mLock);
-    Info& info(mActivationCount.editValueFor(handle));
+    ssize_t activationIndex = mActivationCount.indexOfKey(handle);
+    if (activationIndex < 0) {
+        ALOGW("Handle %d cannot be found in activation record", handle);
+        return BAD_VALUE;
+    }
+    Info& info(mActivationCount.editValueAt(activationIndex));
 
     if (info.batchParams.indexOfKey(ident) < 0) {
         BatchParams params(samplingPeriodNs, maxBatchReportLatencyNs);
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 248ef53..0244c1b 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -28,6 +28,7 @@
 #include <utils/RefBase.h>
 #include <utils/Log.h>
 
+#include <ui/DebugUtils.h>
 #include <ui/DisplayInfo.h>
 #include <ui/PixelFormat.h>
 
@@ -617,6 +618,7 @@
 
 void DisplayDevice::dump(String8& result) const {
     const Transform& tr(mGlobalTransform);
+    ANativeWindow* const window = mNativeWindow.get();
     EGLint redSize, greenSize, blueSize, alphaSize;
     eglGetConfigAttrib(mDisplay, mConfig, EGL_RED_SIZE, &redSize);
     eglGetConfigAttrib(mDisplay, mConfig, EGL_GREEN_SIZE, &greenSize);
@@ -626,9 +628,9 @@
     result.appendFormat("   type=%x, hwcId=%d, layerStack=%u, (%4dx%4d), ANativeWindow=%p "
                         "(%d:%d:%d:%d), orient=%2d (type=%08x), "
                         "flips=%u, isSecure=%d, powerMode=%d, activeConfig=%d, numLayers=%zu\n",
-                        mType, mHwcDisplayId, mLayerStack, mDisplayWidth, mDisplayHeight,
-                        mNativeWindow.get(), redSize, greenSize, blueSize, alphaSize, mOrientation,
-                        tr.getType(), getPageFlipCount(), mIsSecure, mPowerMode, mActiveConfig,
+                        mType, mHwcDisplayId, mLayerStack, mDisplayWidth, mDisplayHeight, window,
+                        redSize, greenSize, blueSize, alphaSize, mOrientation, tr.getType(),
+                        getPageFlipCount(), mIsSecure, mPowerMode, mActiveConfig,
                         mVisibleLayersSortedByZ.size());
     result.appendFormat("   v:[%d,%d,%d,%d], f:[%d,%d,%d,%d], s:[%d,%d,%d,%d],"
                         "transform:[[%0.3f,%0.3f,%0.3f][%0.3f,%0.3f,%0.3f][%0.3f,%0.3f,%0.3f]]\n",
@@ -636,6 +638,9 @@
                         mFrame.left, mFrame.top, mFrame.right, mFrame.bottom, mScissor.left,
                         mScissor.top, mScissor.right, mScissor.bottom, tr[0][0], tr[1][0], tr[2][0],
                         tr[0][1], tr[1][1], tr[2][1], tr[0][2], tr[1][2], tr[2][2]);
+    auto const surface = static_cast<Surface*>(window);
+    android_dataspace dataspace = surface->getBuffersDataSpace();
+    result.appendFormat("   dataspace: %s (%d)\n", dataspaceDetails(dataspace).c_str(), dataspace);
 
     String8 surfaceDump;
     mDisplaySurface->dumpAsString(surfaceDump);
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index e92565f..826b4a8 100755
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -2501,7 +2501,7 @@
 
     const Layer::State& layerState(getDrawingState());
     const HWCInfo& hwcInfo = mHwcLayers.at(hwcId);
-    result.appendFormat("  %10u | ", layerState.z);
+    result.appendFormat("  %10d | ", layerState.z);
     result.appendFormat("%10s | ",
             to_string(getCompositionType(hwcId)).c_str());
     const Rect& frame = hwcInfo.displayFrame;
@@ -2625,6 +2625,44 @@
     return true;
 }
 
+bool Layer::reparentChild(const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle) {
+    if (newParentHandle == nullptr || childHandle == nullptr) {
+        return false;
+    }
+
+    auto handle = static_cast<Handle*>(newParentHandle.get());
+    sp<Layer> newParent = handle->owner.promote();
+    if (newParent == nullptr) {
+        ALOGE("Unable to promote Layer handle");
+        return false;
+    }
+
+    handle = static_cast<Handle*>(childHandle.get());
+    sp<Layer> child = handle->owner.promote();
+    if (child == nullptr) {
+        ALOGE("Unable to promote child Layer handle");
+        return false;
+    }
+
+    if (mCurrentChildren.indexOf(child) < 0) {
+        ALOGE("Child layer is not child of current layer");
+        return false;
+    }
+
+    sp<Client> parentClient(mClientRef.promote());
+    sp<Client> childClient(child->mClientRef.promote());
+    sp<Client> newParentClient(newParent->mClientRef.promote());
+
+    if (parentClient != childClient || childClient != newParentClient) {
+        ALOGE("Current layer, child layer, and new parent layer must have the same client");
+        return false;
+    }
+
+    newParent->addChild(child);
+    mCurrentChildren.remove(child);
+    return true;
+}
+
 bool Layer::detachChildren() {
     traverseInZOrder(LayerVector::StateSet::Drawing, [this](Layer* child) {
         if (child == this) {
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index f7b82e4..f94833b 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -241,6 +241,7 @@
     bool setOverrideScalingMode(int32_t overrideScalingMode);
     void setInfo(uint32_t type, uint32_t appId);
     bool reparentChildren(const sp<IBinder>& layer);
+    bool reparentChild(const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle);
     bool detachChildren();
 
     // If we have received a new buffer this frame, we will pass its surface
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 959d22f..e9d8c96 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2777,7 +2777,14 @@
         if (parent == nullptr) {
             mCurrentState.layersSortedByZ.add(lbc);
         } else {
-            if (mCurrentState.layersSortedByZ.indexOf(parent) < 0) {
+            bool found = false;
+            mCurrentState.traverseInZOrder([&](Layer* layer) {
+                if (layer == parent.get()) {
+                    found = true;
+                }
+            });
+
+            if (!found) {
                 ALOGE("addClientLayer called with a removed parent");
                 return NAME_NOT_FOUND;
             }
@@ -3103,6 +3110,13 @@
             // We don't trigger a traversal here because if no other state is
             // changed, we don't want this to cause any more work
         }
+        // Always re-parent the children that explicitly requested to get
+        // re-parented before the general re-parent of all children.
+        if (what & layer_state_t::eReparentChild) {
+            if (layer->reparentChild(s.parentHandleForChild, s.childHandle)) {
+                flags |= eTransactionNeeded|eTraversalNeeded;
+            }
+        }
         if (what & layer_state_t::eReparentChildren) {
             if (layer->reparentChildren(s.reparentHandle)) {
                 flags |= eTransactionNeeded|eTraversalNeeded;
diff --git a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
index a92e1f9..71aa52d 100644
--- a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
+++ b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
@@ -2679,6 +2679,13 @@
             // We don't trigger a traversal here because if no other state is
             // changed, we don't want this to cause any more work
         }
+        // Always re-parent the children that explicitly requested to get
+        // re-parented before the general re-parent of all children.
+        if (what & layer_state_t::eReparentChild) {
+            if (layer->reparentChild(s.parentHandleForChild, s.childHandle)) {
+                flags |= eTransactionNeeded|eTraversalNeeded;
+            }
+        }
         if (what & layer_state_t::eReparentChildren) {
             if (layer->reparentChildren(s.reparentHandle)) {
                 flags |= eTransactionNeeded|eTraversalNeeded;
diff --git a/services/surfaceflinger/tests/Transaction_test.cpp b/services/surfaceflinger/tests/Transaction_test.cpp
index 4ce14f8..d80ed92 100644
--- a/services/surfaceflinger/tests/Transaction_test.cpp
+++ b/services/surfaceflinger/tests/Transaction_test.cpp
@@ -1123,4 +1123,48 @@
     fillSurfaceRGBA8(mFGSurfaceControl, 0, 255, 0);
 }
 
+TEST_F(ChildLayerTest, ReparentChild) {
+    SurfaceComposerClient::openGlobalTransaction();
+    mChild->show();
+    mChild->setPosition(10, 10);
+    mFGSurfaceControl->setPosition(64, 64);
+    SurfaceComposerClient::closeGlobalTransaction(true);
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // Top left of foreground must now be visible
+        mCapture->expectFGColor(64, 64);
+        // But 10 pixels in we should see the child surface
+        mCapture->expectChildColor(74, 74);
+        // And 10 more pixels we should be back to the foreground surface
+        mCapture->expectFGColor(84, 84);
+    }
+    mFGSurfaceControl->reparentChild(mBGSurfaceControl->getHandle(), mChild->getHandle());
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        mCapture->expectFGColor(64, 64);
+        // In reparenting we should have exposed the entire foreground surface.
+        mCapture->expectFGColor(74, 74);
+        // And the child layer should now begin at 10, 10 (since the BG
+        // layer is at (0, 0)).
+        mCapture->expectBGColor(9, 9);
+        mCapture->expectChildColor(10, 10);
+    }
+}
+
+TEST_F(ChildLayerTest, NestedChildren) {
+    sp<SurfaceControl> grandchild = mComposerClient->createSurface(
+        String8("Grandchild surface"),
+        10, 10, PIXEL_FORMAT_RGBA_8888,
+        0, mChild.get());
+    fillSurfaceRGBA8(grandchild, 50, 50, 50);
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // Expect the grandchild to begin at 64, 64 because it's a child of mChild layer
+        // which begins at 64, 64
+        mCapture->checkPixel(64, 64, 50, 50, 50);
+    }
+}
+
 }
diff --git a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp
index 60916f3..d97ffa3 100644
--- a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp
+++ b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp
@@ -36,7 +36,6 @@
 #include <thread>
 
 constexpr Config NULL_DISPLAY_CONFIG = static_cast<Config>(0);
-constexpr Display DEFAULT_DISPLAY = static_cast<Display>(1);
 
 using namespace sftest;
 
@@ -168,7 +167,7 @@
     ALOGV("enableCallback");
     mCallbacksOn = enable;
     if (mCallbacksOn) {
-        mClient->onHotplug(DEFAULT_DISPLAY, IComposerCallback::Connection::CONNECTED);
+        mClient->onHotplug(PRIMARY_DISPLAY, IComposerCallback::Connection::CONNECTED);
     }
 }
 
@@ -507,7 +506,7 @@
         if (mSurfaceComposer != nullptr) {
             mSurfaceComposer->injectVSync(timestamp);
         } else {
-            mClient->onVsync(DEFAULT_DISPLAY, timestamp);
+            mClient->onVsync(PRIMARY_DISPLAY, timestamp);
         }
     }
 }
diff --git a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
index 294abb2..2a5a8ad 100644
--- a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
+++ b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
@@ -19,6 +19,9 @@
 #include "ComposerClient.h"
 #include "RenderState.h"
 
+// Needed for display type/ID enums
+#include <hardware/hwcomposer_defs.h>
+
 #include <utils/Condition.h>
 
 #include <chrono>
@@ -40,6 +43,13 @@
 
 namespace sftest {
 
+// NOTE: The ID's need to be exactly these. VR composer and parts of
+// the SurfaceFlinger assume the display IDs to have these values
+// despite the enum being documented as a display type.
+// TODO: Reference to actual documentation
+constexpr Display PRIMARY_DISPLAY = static_cast<Display>(HWC_DISPLAY_PRIMARY);
+constexpr Display EXTERNAL_DISPLAY = static_cast<Display>(HWC_DISPLAY_EXTERNAL);
+
 class FakeComposerClient : public ComposerBase {
 public:
     FakeComposerClient();
diff --git a/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp b/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
index 8902ede..9ac3331 100644
--- a/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
+++ b/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
@@ -168,17 +168,15 @@
     android::hardware::ProcessState::self()->startThreadPool();
     android::ProcessState::self()->startThreadPool();
 
-    EXPECT_CALL(*mMockComposer, getDisplayType(1, _))
+    EXPECT_CALL(*mMockComposer, getDisplayType(PRIMARY_DISPLAY, _))
             .WillOnce(DoAll(SetArgPointee<1>(IComposerClient::DisplayType::PHYSICAL),
                             Return(Error::NONE)));
-    // Seems to be doubled right now, once for display ID 1 and once for 0. This sounds fishy
-    // but encoding that here exactly.
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(1, 1, _, _))
-            .Times(5)
-            .WillRepeatedly(Invoke(mMockComposer, &MockComposerClient::getDisplayAttributeFake));
-    // TODO: Find out what code is generating the ID 0.
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(0, 1, _, _))
-            .Times(5)
+    // Primary display will be queried twice for all 5 attributes. One
+    // set of queries comes from the SurfaceFlinger proper an the
+    // other set from the VR composer.
+    // TODO: Is VR composer always present? Change to atLeast(5)?
+    EXPECT_CALL(*mMockComposer, getDisplayAttribute(PRIMARY_DISPLAY, 1, _, _))
+            .Times(2 * 5)
             .WillRepeatedly(Invoke(mMockComposer, &MockComposerClient::getDisplayAttributeFake));
 
     startSurfaceFlinger();
@@ -207,31 +205,32 @@
 TEST_F(DisplayTest, Hotplug) {
     ALOGD("DisplayTest::Hotplug");
 
-    EXPECT_CALL(*mMockComposer, getDisplayType(2, _))
+    EXPECT_CALL(*mMockComposer, getDisplayType(EXTERNAL_DISPLAY, _))
             .Times(2)
             .WillRepeatedly(DoAll(SetArgPointee<1>(IComposerClient::DisplayType::PHYSICAL),
                                   Return(Error::NONE)));
     // The attribute queries will get done twice. This is for defaults
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(2, 1, _, _))
+    EXPECT_CALL(*mMockComposer, getDisplayAttribute(EXTERNAL_DISPLAY, 1, _, _))
             .Times(2 * 3)
             .WillRepeatedly(Invoke(mMockComposer, &MockComposerClient::getDisplayAttributeFake));
     // ... and then special handling for dimensions. Specifying this
     // rules later means that gmock will try them first, i.e.,
     // ordering of width/height vs. the default implementation for
     // other queries is significant.
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(2, 1, IComposerClient::Attribute::WIDTH, _))
+    EXPECT_CALL(*mMockComposer,
+                getDisplayAttribute(EXTERNAL_DISPLAY, 1, IComposerClient::Attribute::WIDTH, _))
             .Times(2)
             .WillRepeatedly(DoAll(SetArgPointee<3>(400), Return(Error::NONE)));
 
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(2, 1, IComposerClient::Attribute::HEIGHT, _))
+    EXPECT_CALL(*mMockComposer,
+                getDisplayAttribute(EXTERNAL_DISPLAY, 1, IComposerClient::Attribute::HEIGHT, _))
             .Times(2)
             .WillRepeatedly(DoAll(SetArgPointee<3>(200), Return(Error::NONE)));
 
     // TODO: Width and height queries are not actually called. Display
     // info returns dimensions 0x0 in display info. Why?
 
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::CONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::CONNECTED);
 
     {
         sp<android::IBinder> display(
@@ -257,13 +256,11 @@
         }
     }
 
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::DISCONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::DISCONNECTED);
 
     mMockComposer->clearFrames();
 
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::CONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::CONNECTED);
 
     {
         sp<android::IBinder> display(
@@ -288,8 +285,7 @@
             ASSERT_EQ(NO_ERROR, surfaceControl->show());
         }
     }
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::DISCONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::DISCONNECTED);
 }
 
 ////////////////////////////////////////////////
@@ -664,7 +660,7 @@
              {{0.f, 1.f, 1.f, 0.f},     HWC_TRANSFORM_FLIP_H_ROT_90,    {64, 64, 128, 128}},
              {{0.f, 1.f, 1.f, 0.f},     HWC_TRANSFORM_FLIP_V_ROT_90,    {64, 64, 128, 128}}};
     // clang-format on
-    constexpr int TEST_COUNT = sizeof(MATRIX_TESTS)/sizeof(matrixTestData);
+    constexpr int TEST_COUNT = sizeof(MATRIX_TESTS) / sizeof(matrixTestData);
 
     for (int i = 0; i < TEST_COUNT; i++) {
         // TODO: How to leverage the HWC2 stringifiers?
diff --git a/services/surfaceflinger/tests/hwc2/Android.mk b/services/surfaceflinger/tests/hwc2/Android.mk
index 203ced5..6d20349 100644
--- a/services/surfaceflinger/tests/hwc2/Android.mk
+++ b/services/surfaceflinger/tests/hwc2/Android.mk
@@ -36,7 +36,9 @@
     libui \
     libgui \
     liblog \
-    libsync
+    libsync \
+    libskia \
+    android.hardware.graphics.common@1.0
 LOCAL_STATIC_LIBRARIES := \
     libbase \
     libadf \
@@ -49,6 +51,7 @@
     Hwc2TestLayers.cpp \
     Hwc2TestBuffer.cpp \
     Hwc2TestClientTarget.cpp \
-    Hwc2TestVirtualDisplay.cpp
+    Hwc2TestVirtualDisplay.cpp \
+    Hwc2TestPixelComparator.cpp
 
 include $(BUILD_NATIVE_TEST)
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp b/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp
index 4055527..4878c14 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp
@@ -1775,6 +1775,145 @@
         }
     }
 
+    void createAndPresentVirtualDisplay(size_t layerCnt,
+            Hwc2TestCoverage coverage,
+            const std::unordered_map<Hwc2TestPropertyName, Hwc2TestCoverage>&
+            coverageExceptions)
+    {
+        Hwc2TestVirtualDisplay testVirtualDisplay(coverage);
+        hwc2_display_t display;
+        android_pixel_format_t desiredFormat = HAL_PIXEL_FORMAT_RGBA_8888;
+
+        do {
+            // Items dependent on the display dimensions
+            hwc2_error_t err = HWC2_ERROR_NONE;
+            const UnsignedArea& dimension =
+                    testVirtualDisplay.getDisplayDimension();
+            ASSERT_NO_FATAL_FAILURE(createVirtualDisplay(dimension.width,
+                    dimension.height, &desiredFormat, &display, &err));
+            ASSERT_TRUE(err == HWC2_ERROR_NONE)
+                    << "Cannot allocate virtual display";
+
+            ASSERT_NO_FATAL_FAILURE(setPowerMode(display, HWC2_POWER_MODE_ON));
+            ASSERT_NO_FATAL_FAILURE(enableVsync(display));
+
+            std::vector<hwc2_config_t> configs;
+            ASSERT_NO_FATAL_FAILURE(getDisplayConfigs(display, &configs));
+
+            for (auto config : configs) {
+                ASSERT_NO_FATAL_FAILURE(setActiveConfig(display, config));
+
+                Area displayArea;
+                ASSERT_NO_FATAL_FAILURE(getActiveDisplayArea(display,
+                        &displayArea));
+
+                std::vector<hwc2_layer_t> layers;
+                ASSERT_NO_FATAL_FAILURE(createLayers(display, &layers,
+                        layerCnt));
+                Hwc2TestLayers testLayers(layers, coverage, displayArea,
+                        coverageExceptions);
+
+                /*
+                 * Layouts that do not cover an entire virtual display will
+                 * cause undefined behavior.
+                 * Enable optimizeLayouts to avoid this.
+                 */
+                testLayers.optimizeLayouts();
+                do {
+                    // Items dependent on the testLayers properties
+                    std::set<hwc2_layer_t> clientLayers;
+                    std::set<hwc2_layer_t> clearLayers;
+                    uint32_t numTypes, numRequests;
+                    bool hasChanges, skip;
+                    bool flipClientTarget;
+                    int32_t presentFence;
+                    Hwc2TestClientTarget testClientTarget;
+                    buffer_handle_t outputBufferHandle;
+                    android::base::unique_fd outputBufferReleaseFence;
+
+                    ASSERT_NO_FATAL_FAILURE(setLayerProperties(display, layers,
+                            &testLayers, &skip));
+
+                    if (skip)
+                        continue;
+
+                    ASSERT_NO_FATAL_FAILURE(validateDisplay(display, &numTypes,
+                            &numRequests, &hasChanges));
+
+                    if (hasChanges)
+                        EXPECT_LE(numTypes, static_cast<uint32_t>(layers.size()))
+                                << "wrong number of requests";
+
+                    ASSERT_NO_FATAL_FAILURE(handleCompositionChanges(display,
+                            testLayers, layers, numTypes, &clientLayers));
+
+                    ASSERT_NO_FATAL_FAILURE(handleRequests(display, layers,
+                            numRequests, &clearLayers, &flipClientTarget));
+                    ASSERT_NO_FATAL_FAILURE(setClientTarget(display,
+                            &testClientTarget, testLayers, clientLayers,
+                            clearLayers, flipClientTarget, displayArea));
+                    ASSERT_NO_FATAL_FAILURE(acceptDisplayChanges(display));
+
+                    ASSERT_EQ(testVirtualDisplay.getOutputBuffer(
+                            &outputBufferHandle, &outputBufferReleaseFence), 0);
+                    ASSERT_NO_FATAL_FAILURE(setOutputBuffer(display,
+                            outputBufferHandle, outputBufferReleaseFence));
+
+                    EXPECT_NO_FATAL_FAILURE(presentDisplay(display,
+                            &presentFence));
+                    ASSERT_NO_FATAL_FAILURE(closeFences(display, presentFence));
+
+                    ASSERT_EQ(testVirtualDisplay.verifyOutputBuffer(&testLayers,
+                            &layers, &clearLayers), 0);
+
+                    /*
+                     * Upscaling the image causes minor pixel differences.
+                     * Work around this by using some threshold.
+                     *
+                     * Fail test if we are off by more than 1% of our
+                     * pixels.
+                     */
+                    ComparatorResult& comparatorResult = ComparatorResult::get();
+                    int threshold = (dimension.width * dimension.height) / 100;
+                    double diffPercent = (comparatorResult.getDifferentPixelCount() * 100.0) /
+                            (dimension.width * dimension.height);
+
+                    if (comparatorResult.getDifferentPixelCount() != 0)
+                        EXPECT_TRUE(false)
+                                << comparatorResult.getDifferentPixelCount() << " pixels ("
+                                << diffPercent << "%) are different.";
+
+                    if (comparatorResult.getDifferentPixelCount() > threshold) {
+                        EXPECT_TRUE(false)
+                                << "Mismatched pixel count exceeds threshold. "
+                                << "Writing buffers to file.";
+
+                        const ::testing::TestInfo* const test_info =
+                                ::testing::UnitTest::GetInstance()
+                                ->current_test_info();
+
+                        EXPECT_EQ(testVirtualDisplay.writeBuffersToFile(
+                                test_info->name()), 0)
+                                << "Failed to write buffers.";
+                    }
+
+                    ASSERT_LE(comparatorResult.getDifferentPixelCount(), threshold)
+                            << comparatorResult.getDifferentPixelCount() << " pixels ("
+                            << diffPercent << "%) are different. "
+                            << "Exceeds 1% threshold, terminating test. "
+                            << "Test case: " << testLayers.dump();
+
+                } while (testLayers.advance());
+
+                ASSERT_NO_FATAL_FAILURE(destroyLayers(display,
+                        std::move(layers)));
+            }
+            ASSERT_NO_FATAL_FAILURE(disableVsync(display));
+            ASSERT_NO_FATAL_FAILURE(setPowerMode(display, HWC2_POWER_MODE_OFF));
+            ASSERT_NO_FATAL_FAILURE(destroyVirtualDisplay(display));
+        } while (testVirtualDisplay.advance());
+    }
+
     hwc2_device_t* mHwc2Device = nullptr;
 
     enum class Hwc2TestHotplugStatus {
@@ -4479,7 +4618,7 @@
                 buffer_handle_t handle;
                 android::base::unique_fd acquireFence;
 
-                if (testVirtualDisplay->getBuffer(&handle, &acquireFence) >= 0)
+                if (testVirtualDisplay->getOutputBuffer(&handle, &acquireFence) >= 0)
                     EXPECT_NO_FATAL_FAILURE(test->setOutputBuffer(display,
                             handle, acquireFence));
             }));
@@ -4499,7 +4638,7 @@
 
                 ASSERT_NO_FATAL_FAILURE(test->getBadDisplay(&badDisplay));
 
-                if (testVirtualDisplay->getBuffer(&handle, &acquireFence) < 0)
+                if (testVirtualDisplay->getOutputBuffer(&handle, &acquireFence) < 0)
                     return;
 
                 ASSERT_NO_FATAL_FAILURE(test->setOutputBuffer(badDisplay,
@@ -4539,7 +4678,7 @@
             android::base::unique_fd acquireFence;
             hwc2_error_t err = HWC2_ERROR_NONE;
 
-            if (testVirtualDisplay.getBuffer(&handle, &acquireFence) < 0)
+            if (testVirtualDisplay.getOutputBuffer(&handle, &acquireFence) < 0)
                 continue;
 
             ASSERT_NO_FATAL_FAILURE(setOutputBuffer(display, handle,
@@ -4557,3 +4696,74 @@
 
     ASSERT_NO_FATAL_FAILURE(dump(&buffer));
 }
+
+/*
+ * TODO(b/64724708): Hwc2TestPropertyName::BufferArea MUST be default for all
+ * virtual display tests as we don't handle this case correctly.
+ *
+ * Only default dataspace is supported in our drawing code.
+ */
+const std::unordered_map<Hwc2TestPropertyName, Hwc2TestCoverage>
+        virtualDisplayExceptions =
+        {{Hwc2TestPropertyName::BufferArea, Hwc2TestCoverage::Default},
+        {Hwc2TestPropertyName::Dataspace, Hwc2TestCoverage::Default}};
+
+/* TESTCASE: Tests that the HWC2 can present 1 layer with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_1)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 1;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 1 layer with basic coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_basic_1)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Basic;
+    const size_t layerCnt = 1;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 2 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_2)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 2;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 3 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_3)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 3;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 4 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_4)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 4;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 5 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_5)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 5;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp
index 1d3a1d3..6484562 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp
@@ -23,14 +23,17 @@
 #include <gui/BufferItemConsumer.h>
 
 #include <ui/GraphicBuffer.h>
+#include <android/hardware/graphics/common/1.0/types.h>
 #include <math/vec4.h>
 
 #include <GLES3/gl3.h>
-
+#include <SkImageEncoder.h>
+#include <SkStream.h>
 #include "Hwc2TestBuffer.h"
 #include "Hwc2TestLayers.h"
 
 using namespace android;
+using android::hardware::graphics::common::V1_0::BufferUsage;
 
 /* Returns a fence from egl */
 typedef void (*FenceCallback)(int32_t fence, void* callbackArgs);
@@ -396,8 +399,9 @@
 {
     /* Create new graphic buffer with correct dimensions */
     mGraphicBuffer = new GraphicBuffer(mBufferArea.width, mBufferArea.height,
-            mFormat, GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_HW_RENDER,
-            "hwc2_test_buffer");
+            mFormat, BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN |
+            BufferUsage::COMPOSER_OVERLAY, "hwc2_test_buffer");
+
     int ret = mGraphicBuffer->initCheck();
     if (ret) {
         return ret;
@@ -408,7 +412,8 @@
 
     /* Locks the buffer for writing */
     uint8_t* img;
-    mGraphicBuffer->lock(GRALLOC_USAGE_SW_WRITE_OFTEN, (void**)(&img));
+    mGraphicBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_WRITE_OFTEN),
+            (void**)(&img));
 
     uint32_t stride = mGraphicBuffer->getStride();
 
@@ -458,31 +463,22 @@
 
 Hwc2TestClientTargetBuffer::~Hwc2TestClientTargetBuffer() { }
 
-/* Generates a client target buffer using the layers assigned for client
- * composition. Takes into account the individual layer properties such as
+/* Generates a buffer from layersToDraw.
+ * Takes into account the individual layer properties such as
  * transform, blend mode, source crop, etc. */
-int Hwc2TestClientTargetBuffer::get(buffer_handle_t* outHandle,
-        int32_t* outFence, const Area& bufferArea,
+static void compositeBufferFromLayers(
+        const android::sp<android::GraphicBuffer>& graphicBuffer,
+        android_pixel_format_t format, const Area& bufferArea,
         const Hwc2TestLayers* testLayers,
-        const std::set<hwc2_layer_t>* clientLayers,
+        const std::set<hwc2_layer_t>* layersToDraw,
         const std::set<hwc2_layer_t>* clearLayers)
 {
-    /* Create new graphic buffer with correct dimensions */
-    mGraphicBuffer = new GraphicBuffer(bufferArea.width, bufferArea.height,
-            mFormat, GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_HW_RENDER,
-            "hwc2_test_buffer");
-    int ret = mGraphicBuffer->initCheck();
-    if (ret) {
-        return ret;
-    }
-    if (!mGraphicBuffer->handle) {
-        return -EINVAL;
-    }
-
+    /* Locks the buffer for writing */
     uint8_t* img;
-    mGraphicBuffer->lock(GRALLOC_USAGE_SW_WRITE_OFTEN, (void**)(&img));
+    graphicBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_WRITE_OFTEN),
+            (void**)(&img));
 
-    uint32_t stride = mGraphicBuffer->getStride();
+    uint32_t stride = graphicBuffer->getStride();
 
     float bWDiv3 = bufferArea.width / 3;
     float bW2Div3 = bufferArea.width * 2 / 3;
@@ -497,10 +493,10 @@
             uint8_t r = 0, g = 0, b = 0;
             float a = 0.0f;
 
-            /* Cycle through each client layer from back to front and
+            /* Cycle through each layer from back to front and
              * update the pixel color. */
-            for (auto layer = clientLayers->rbegin();
-                    layer != clientLayers->rend(); ++layer) {
+            for (auto layer = layersToDraw->rbegin();
+                    layer != layersToDraw->rend(); ++layer) {
 
                 const hwc_rect_t df = testLayers->getDisplayFrame(*layer);
 
@@ -570,8 +566,8 @@
                      * (100x50) at the end of the transformation. */
                     if (transform & HWC_TRANSFORM_ROT_90) {
                         float tmp = xPos;
-                        xPos = -yPos * dfW / dfH;
-                        yPos = tmp * dfH / dfW;
+                        xPos = yPos * dfW / dfH;
+                        yPos = -tmp * dfH / dfW;
                     }
 
                     /* Change origin back to the top left corner of the
@@ -682,14 +678,114 @@
             }
 
             /* Set the pixel color */
-            setColor(x, y, mFormat, stride, img, r, g, b, a * 255);
+            setColor(x, y, format, stride, img, r, g, b, a * 255);
         }
     }
 
-    mGraphicBuffer->unlock();
+    graphicBuffer->unlock();
+}
+
+/* Generates a client target buffer using the layers assigned for client
+ * composition. Takes into account the individual layer properties such as
+ * transform, blend mode, source crop, etc. */
+int Hwc2TestClientTargetBuffer::get(buffer_handle_t* outHandle,
+        int32_t* outFence, const Area& bufferArea,
+        const Hwc2TestLayers* testLayers,
+        const std::set<hwc2_layer_t>* clientLayers,
+        const std::set<hwc2_layer_t>* clearLayers)
+{
+    /* Create new graphic buffer with correct dimensions */
+    mGraphicBuffer = new GraphicBuffer(bufferArea.width, bufferArea.height,
+            mFormat, BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN |
+            BufferUsage::COMPOSER_OVERLAY, "hwc2_test_buffer");
+
+    int ret = mGraphicBuffer->initCheck();
+    if (ret)
+        return ret;
+
+    if (!mGraphicBuffer->handle)
+        return -EINVAL;
+
+    compositeBufferFromLayers(mGraphicBuffer, mFormat, bufferArea, testLayers,
+            clientLayers, clearLayers);
 
     *outFence = mFenceGenerator->get();
     *outHandle = mGraphicBuffer->handle;
 
     return 0;
 }
+
+void Hwc2TestVirtualBuffer::updateBufferArea(const Area& bufferArea)
+{
+    mBufferArea.width = bufferArea.width;
+    mBufferArea.height = bufferArea.height;
+}
+
+bool Hwc2TestVirtualBuffer::writeBufferToFile(std::string path)
+{
+    SkFILEWStream file(path.c_str());
+    const SkImageInfo info = SkImageInfo::Make(mBufferArea.width,
+            mBufferArea.height, SkColorType::kRGBA_8888_SkColorType,
+            SkAlphaType::kPremul_SkAlphaType);
+
+    uint8_t* img;
+    mGraphicBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_WRITE_OFTEN),
+            (void**)(&img));
+
+    SkPixmap pixmap(info, img, mGraphicBuffer->getStride());
+    bool result = file.isValid() && SkEncodeImage(&file, pixmap,
+            SkEncodedImageFormat::kPNG, 100);
+
+    mGraphicBuffer->unlock();
+    return result;
+}
+
+/* Generates a buffer that holds the expected result of compositing all of our
+ * layers */
+int Hwc2TestExpectedBuffer::generateExpectedBuffer(
+        const Hwc2TestLayers* testLayers,
+        const std::vector<hwc2_layer_t>* allLayers,
+        const std::set<hwc2_layer_t>* clearLayers)
+{
+    mGraphicBuffer = new GraphicBuffer(mBufferArea.width, mBufferArea.height,
+            mFormat, BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN,
+            "hwc2_test_buffer");
+
+    int ret = mGraphicBuffer->initCheck();
+    if (ret)
+        return ret;
+
+    if (!mGraphicBuffer->handle)
+        return -EINVAL;
+
+    const std::set<hwc2_layer_t> allLayerSet(allLayers->begin(),
+            allLayers->end());
+
+    compositeBufferFromLayers(mGraphicBuffer, mFormat, mBufferArea, testLayers,
+            &allLayerSet, clearLayers);
+
+    return 0;
+}
+
+int Hwc2TestOutputBuffer::getOutputBuffer(buffer_handle_t* outHandle,
+        int32_t* outFence)
+{
+    if (mBufferArea.width == -1 || mBufferArea.height == -1)
+        return -EINVAL;
+
+    mGraphicBuffer = new GraphicBuffer(mBufferArea.width, mBufferArea.height,
+            mFormat, BufferUsage::CPU_READ_OFTEN |
+            BufferUsage::GPU_RENDER_TARGET, "hwc2_test_buffer");
+
+    int ret = mGraphicBuffer->initCheck();
+    if (ret)
+        return ret;
+
+    if (!mGraphicBuffer->handle)
+        return -EINVAL;
+
+    *outFence = -1;
+    *outHandle = mGraphicBuffer->handle;
+
+    return 0;
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h
index b2b3a66..fd54fef 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h
@@ -71,4 +71,38 @@
     const android_pixel_format_t mFormat = HAL_PIXEL_FORMAT_RGBA_8888;
 };
 
+
+class Hwc2TestVirtualBuffer {
+public:
+    void updateBufferArea(const Area& bufferArea);
+
+    bool writeBufferToFile(std::string path);
+
+    android::sp<android::GraphicBuffer>& graphicBuffer()
+    {
+        return mGraphicBuffer;
+    }
+
+protected:
+    android::sp<android::GraphicBuffer> mGraphicBuffer;
+
+    Area mBufferArea = {-1, -1};
+
+    const android_pixel_format_t mFormat = HAL_PIXEL_FORMAT_RGBA_8888;
+};
+
+
+class Hwc2TestExpectedBuffer : public Hwc2TestVirtualBuffer {
+public:
+    int generateExpectedBuffer(const Hwc2TestLayers* testLayers,
+            const std::vector<hwc2_layer_t>* allLayers,
+            const std::set<hwc2_layer_t>* clearLayers);
+};
+
+
+class Hwc2TestOutputBuffer : public Hwc2TestVirtualBuffer {
+public:
+    int getOutputBuffer(buffer_handle_t* outHandle, int32_t* outFence);
+};
+
 #endif /* ifndef _HWC2_TEST_BUFFER_H */
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.cpp
new file mode 100644
index 0000000..904b927
--- /dev/null
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sstream>
+#include <android/hardware/graphics/common/1.0/types.h>
+
+#include "Hwc2TestPixelComparator.h"
+
+using android::hardware::graphics::common::V1_0::BufferUsage;
+
+uint32_t ComparatorResult::getPixel(int32_t x, int32_t y, uint32_t stride,
+        uint8_t* img) const
+{
+    uint32_t r = img[(y * stride + x) * 4 + 0];
+    uint32_t g = img[(y * stride + x) * 4 + 1];
+    uint32_t b = img[(y * stride + x) * 4 + 2];
+    uint32_t a = img[(y * stride + x) * 4 + 3];
+
+    uint32_t pixel = 0;
+    pixel |= r;
+    pixel |= g << 8;
+    pixel |= b << 16;
+    pixel |= a << 24;
+    return pixel;
+}
+
+void ComparatorResult::CompareBuffers(
+        android::sp<android::GraphicBuffer>& resultBuffer,
+        android::sp<android::GraphicBuffer>& expectedBuffer)
+{
+    uint8_t* resultBufferImg;
+    uint8_t* expectedBufferImg;
+    resultBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_READ_OFTEN),
+            (void**)(&resultBufferImg));
+
+    expectedBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_READ_OFTEN),
+            (void**)(&expectedBufferImg));
+    mComparisons.clear();
+    int32_t mDifferentPixelCount = 0;
+    int32_t mBlankPixelCount = 0;
+
+    for (uint32_t y = 0; y < resultBuffer->getHeight(); y++) {
+        for (uint32_t x = 0; x < resultBuffer->getWidth(); x++) {
+            uint32_t result = getPixel(x, y, resultBuffer->getStride(),
+                    resultBufferImg);
+            uint32_t expected = getPixel(x, y, expectedBuffer->getStride(),
+                    expectedBufferImg);
+
+            if (result == 0)
+                mBlankPixelCount++;
+
+            if (result != expected)
+                mDifferentPixelCount++;
+
+            mComparisons.emplace_back(std::make_tuple(x, y, result, expected));
+        }
+    }
+    resultBuffer->unlock();
+    expectedBuffer->unlock();
+}
+
+std::string ComparatorResult::pixelDiff(uint32_t x, uint32_t y,
+        uint32_t resultPixel, uint32_t expectedPixel) const
+{
+    uint32_t resultAlpha = (resultPixel >> 24) & 0xFF;
+    uint32_t resultBlue = (resultPixel >> 16) & 0xFF;
+    uint32_t resultGreen = (resultPixel >> 8) & 0xFF;
+    uint32_t resultRed = resultPixel & 0xFF;
+
+    uint32_t expectedAlpha = (expectedPixel >> 24) & 0xFF;
+    uint32_t expectedBlue = (expectedPixel >> 16) & 0xFF;
+    uint32_t expectedGreen = (expectedPixel >> 8) & 0xFF;
+    uint32_t expectedRed = expectedPixel & 0xFF;
+
+    std::ostringstream stream;
+
+    stream << "x: " << x << " y: " << y << std::endl;
+    stream << std::hex;
+    stream << "Result pixel:   " << resultRed << "|" << resultGreen << "|"
+           << resultBlue << "|" << resultAlpha << std::endl;
+
+    stream << "Expected pixel: " << expectedRed << "|" << expectedGreen << "|"
+           << expectedBlue << "|" << expectedAlpha << std::endl;
+
+    return stream.str();
+}
+
+std::string ComparatorResult::dumpComparison() const
+{
+    std::ostringstream stream;
+    stream << "Number of different pixels: " << mDifferentPixelCount;
+
+    for (const auto& comparison : mComparisons) {
+        if (std::get<2>(comparison) != std::get<3>(comparison))
+            stream << pixelDiff(std::get<0>(comparison),
+                    std::get<1>(comparison), std::get<2>(comparison),
+                    std::get<3>(comparison));
+    }
+    return stream.str();
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.h b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.h
new file mode 100644
index 0000000..55fa936
--- /dev/null
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef _HWC2_TEST_PIXEL_COMPARATOR_H
+#define _HWC2_TEST_PIXEL_COMPARATOR_H
+
+#include <ui/GraphicBuffer.h>
+#include <cstdint>
+#include <string>
+#include <utility>
+#include <vector>
+
+class ComparatorResult {
+public:
+    static ComparatorResult& get()
+    {
+        static ComparatorResult instance;
+        return instance;
+    }
+
+    void CompareBuffers(android::sp<android::GraphicBuffer>& resultBuffer,
+            android::sp<android::GraphicBuffer>& expectedBuffer);
+
+    std::string dumpComparison() const;
+
+    ComparatorResult(const ComparatorResult&) = delete;
+    ComparatorResult(ComparatorResult&&) = delete;
+    ComparatorResult& operator=(ComparatorResult const&) = delete;
+    ComparatorResult& operator=(ComparatorResult&&) = delete;
+
+    int32_t getDifferentPixelCount() const { return mDifferentPixelCount; }
+    int32_t getBlankPixelCount() const { return mBlankPixelCount; }
+
+private:
+    ComparatorResult() = default;
+    uint32_t getPixel(int32_t x, int32_t y, uint32_t stride, uint8_t* img) const;
+    std::string pixelDiff(uint32_t x, uint32_t y, uint32_t resultPixel,
+            uint32_t expectedPixel) const;
+
+    int32_t mDifferentPixelCount;
+    int32_t mBlankPixelCount;
+    /* std::tuple<X coordinate, Y coordinate, resultPixel, expectedPixel> */
+    std::vector<std::tuple<uint32_t, uint32_t, uint32_t, uint32_t>>
+            mComparisons;
+};
+
+#endif /* ifndef _HWC2_TEST_PIXEL_COMPARATOR_H */
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp
index b5522de..5b3bbeb 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp
@@ -335,9 +335,9 @@
     return dmp.str();
 }
 
-void Hwc2TestDisplayDimension::setDependent(Hwc2TestBuffer* buffer)
+void Hwc2TestDisplayDimension::setDependent(Hwc2TestVirtualBuffer* buffer)
 {
-    mBuffer = buffer;
+    mBuffers.insert(buffer);
     updateDependents();
 }
 
@@ -345,8 +345,8 @@
 {
     const UnsignedArea& curr = get();
 
-    if (mBuffer)
-        mBuffer->updateBufferArea({static_cast<int32_t>(curr.width),
+    for (Hwc2TestVirtualBuffer* buffer : mBuffers)
+        buffer->updateBufferArea({static_cast<int32_t>(curr.width),
                 static_cast<int32_t>(curr.height)});
 }
 
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h
index c2029ab..cb811e0 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h
@@ -243,6 +243,7 @@
     static const std::array<bool, 6> mCompositionSupport;
 };
 
+class Hwc2TestVirtualBuffer;
 
 class Hwc2TestDisplayDimension : public Hwc2TestProperty<UnsignedArea> {
 public:
@@ -250,12 +251,12 @@
 
     std::string dump() const;
 
-    void setDependent(Hwc2TestBuffer* buffer);
+    void setDependent(Hwc2TestVirtualBuffer* buffer);
 
 private:
     void updateDependents();
 
-    Hwc2TestBuffer* mBuffer;
+    std::set<Hwc2TestVirtualBuffer*> mBuffers;
 
     static const std::vector<UnsignedArea> mDefaultDisplayDimensions;
     static const std::vector<UnsignedArea> mBasicDisplayDimensions;
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp
index d0fbc0b..e6cceb8 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp
@@ -15,14 +15,18 @@
  */
 
 #include <sstream>
+#include <sys/stat.h>
 
 #include "Hwc2TestVirtualDisplay.h"
 
+#define DIR_NAME "images"
+
 Hwc2TestVirtualDisplay::Hwc2TestVirtualDisplay(
         Hwc2TestCoverage coverage)
     : mDisplayDimension(coverage)
 {
-    mDisplayDimension.setDependent(&mBuffer);
+    mDisplayDimension.setDependent(&mOutputBuffer);
+    mDisplayDimension.setDependent(&mExpectedBuffer);
 }
 
 std::string Hwc2TestVirtualDisplay::dump() const
@@ -36,11 +40,11 @@
     return dmp.str();
 }
 
-int Hwc2TestVirtualDisplay::getBuffer(buffer_handle_t* outHandle,
+int Hwc2TestVirtualDisplay::getOutputBuffer(buffer_handle_t* outHandle,
         android::base::unique_fd* outAcquireFence)
 {
     int32_t acquireFence;
-    int ret = mBuffer.get(outHandle, &acquireFence);
+    int ret = mOutputBuffer.getOutputBuffer(outHandle, &acquireFence);
     outAcquireFence->reset(acquireFence);
     return ret;
 }
@@ -59,3 +63,36 @@
 {
     return mDisplayDimension.get();
 }
+
+int Hwc2TestVirtualDisplay::verifyOutputBuffer(const Hwc2TestLayers* testLayers,
+        const std::vector<hwc2_layer_t>* allLayers,
+        const std::set<hwc2_layer_t>* clearLayers)
+{
+    int ret = mExpectedBuffer.generateExpectedBuffer(testLayers, allLayers,
+            clearLayers);
+    if (ret)
+        return ret;
+
+    ComparatorResult::get().CompareBuffers(mOutputBuffer.graphicBuffer(),
+        mExpectedBuffer.graphicBuffer());
+
+    return 0;
+}
+
+int Hwc2TestVirtualDisplay::writeBuffersToFile(std::string name)
+{
+    std::ostringstream expectedPath;
+    std::ostringstream resultPath;
+    int ret = mkdir(DIR_NAME, DEFFILEMODE);
+    if (ret && errno != EEXIST)
+        return ret;
+
+    expectedPath << DIR_NAME << "/expected-" << name << ".png";
+    resultPath << DIR_NAME << "/result-" << name << ".png";
+
+    if (!mExpectedBuffer.writeBufferToFile(expectedPath.str()) ||
+            !mOutputBuffer.writeBufferToFile(resultPath.str()))
+        return -1;
+
+    return 0;
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h
index 09420ef..10c8ef0 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h
@@ -18,6 +18,7 @@
 #define _HWC2_TEST_VIRTUAL_DISPLAY_H
 
 #include "Hwc2TestBuffer.h"
+#include "Hwc2TestPixelComparator.h"
 #include "Hwc2TestProperties.h"
 
 #define HWC2_INCLUDE_STRINGIFICATION
@@ -32,17 +33,22 @@
 
     std::string dump() const;
 
-    int getBuffer(buffer_handle_t* outHandle,
+    int getOutputBuffer(buffer_handle_t* outHandle,
             android::base::unique_fd* outAcquireFence);
 
+    int verifyOutputBuffer(const Hwc2TestLayers* testLayers,
+            const std::vector<hwc2_layer_t>* allLayers,
+            const std::set<hwc2_layer_t>* clearLayers);
+
+    int writeBuffersToFile(std::string name);
     void reset();
     bool advance();
 
     UnsignedArea getDisplayDimension() const;
 
 private:
-    Hwc2TestBuffer mBuffer;
-
+    Hwc2TestOutputBuffer mOutputBuffer;
+    Hwc2TestExpectedBuffer mExpectedBuffer;
     Hwc2TestDisplayDimension mDisplayDimension;
 };