diff --git a/data/etc/android.hardware.telephony.satellite.xml b/data/etc/android.hardware.telephony.satellite.xml
index d36c958..5966cba 100644
--- a/data/etc/android.hardware.telephony.satellite.xml
+++ b/data/etc/android.hardware.telephony.satellite.xml
@@ -14,7 +14,7 @@
      limitations under the License.
 -->
 
-<!-- Feature for devices that support satellite communication via satellite vendor service APIs. -->
+<!-- Feature for devices that support Satellite communication via Satellite HAL APIs. -->
 <permissions>
     <feature name="android.hardware.telephony.satellite" />
 </permissions>
diff --git a/include/android/keycodes.h b/include/android/keycodes.h
index d4ba321..f8fb256 100644
--- a/include/android/keycodes.h
+++ b/include/android/keycodes.h
@@ -831,6 +831,14 @@
     AKEYCODE_STYLUS_BUTTON_TAIL = 311,
     /** Key to open recent apps (a.k.a. Overview) */
     AKEYCODE_RECENT_APPS = 312,
+    /** User customizable key #1. */
+    AKEYCODE_MACRO_1 = 313,
+    /** User customizable key #2. */
+    AKEYCODE_MACRO_2 = 314,
+    /** User customizable key #3. */
+    AKEYCODE_MACRO_3 = 315,
+    /** User customizable key #4. */
+    AKEYCODE_MACRO_4 = 316,
 
     // NOTE: If you add a new keycode here you must also add it to several other files.
     //       Refer to frameworks/base/core/java/android/view/KeyEvent.java for the full list.
diff --git a/include/input/RingBuffer.h b/include/input/RingBuffer.h
index 67984b7..5e9972e 100644
--- a/include/input/RingBuffer.h
+++ b/include/input/RingBuffer.h
@@ -24,7 +24,6 @@
 #include <type_traits>
 #include <utility>
 
-#include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 
 namespace android {
@@ -272,15 +271,16 @@
 
     // Converts the index of an element in [0, size()] to its corresponding index in mBuffer.
     size_type bufferIndex(size_type elementIndex) const {
-        CHECK_LE(elementIndex, size());
+        if (elementIndex > size()) {
+            abort();
+        }
         size_type index = mBegin + elementIndex;
         if (index >= capacity()) {
             index -= capacity();
         }
-        CHECK_LT(index, capacity())
-                << android::base::StringPrintf("Invalid index calculated for element (%zu) "
-                                               "in buffer of size %zu",
-                                               elementIndex, size());
+        if (index >= capacity()) {
+            abort();
+        }
         return index;
     }
 
diff --git a/include/input/VelocityControl.h b/include/input/VelocityControl.h
index f3c201e..b78f63e 100644
--- a/include/input/VelocityControl.h
+++ b/include/input/VelocityControl.h
@@ -88,7 +88,7 @@
     VelocityControl();
 
     /* Gets the various parameters. */
-    VelocityControlParameters& getParameters();
+    const VelocityControlParameters& getParameters() const;
 
     /* Sets the various parameters. */
     void setParameters(const VelocityControlParameters& parameters);
diff --git a/include/input/VelocityTracker.h b/include/input/VelocityTracker.h
index da97c3e..b58feac 100644
--- a/include/input/VelocityTracker.h
+++ b/include/input/VelocityTracker.h
@@ -17,6 +17,7 @@
 #pragma once
 
 #include <input/Input.h>
+#include <input/RingBuffer.h>
 #include <utils/BitSet.h>
 #include <utils/Timers.h>
 #include <map>
@@ -31,6 +32,8 @@
  */
 class VelocityTracker {
 public:
+    static const size_t MAX_DEGREE = 4;
+
     enum class Strategy : int32_t {
         DEFAULT = -1,
         MIN = 0,
@@ -47,23 +50,6 @@
         MAX = LEGACY,
     };
 
-    struct Estimator {
-        static const size_t MAX_DEGREE = 4;
-
-        // Estimator time base.
-        nsecs_t time = 0;
-
-        // Polynomial coefficients describing motion.
-        std::array<float, MAX_DEGREE + 1> coeff{};
-
-        // Polynomial degree (number of coefficients), or zero if no information is
-        // available.
-        uint32_t degree = 0;
-
-        // Confidence (coefficient of determination), between 0 (no fit) and 1 (perfect fit).
-        float confidence = 0;
-    };
-
     /*
      * Contains all available velocity data from a VelocityTracker.
      */
@@ -124,11 +110,6 @@
     // [-maxVelocity, maxVelocity], inclusive.
     ComputedVelocity getComputedVelocity(int32_t units, float maxVelocity);
 
-    // Gets an estimator for the recent movements of the specified pointer id for the given axis.
-    // Returns false and clears the estimator if there is no information available
-    // about the pointer.
-    std::optional<Estimator> getEstimator(int32_t axis, int32_t pointerId) const;
-
     // Gets the active pointer id, or -1 if none.
     inline int32_t getActivePointerId() const { return mActivePointerId.value_or(-1); }
 
@@ -169,14 +150,48 @@
 
     virtual void clearPointer(int32_t pointerId) = 0;
     virtual void addMovement(nsecs_t eventTime, int32_t pointerId, float position) = 0;
-    virtual std::optional<VelocityTracker::Estimator> getEstimator(int32_t pointerId) const = 0;
+    virtual std::optional<float> getVelocity(int32_t pointerId) const = 0;
 };
 
+/**
+ * A `VelocityTrackerStrategy` that accumulates added data points and processes the accumulated data
+ * points when getting velocity.
+ */
+class AccumulatingVelocityTrackerStrategy : public VelocityTrackerStrategy {
+public:
+    AccumulatingVelocityTrackerStrategy(nsecs_t horizonNanos, bool maintainHorizonDuringAdd);
+
+    void addMovement(nsecs_t eventTime, int32_t pointerId, float position) override;
+    void clearPointer(int32_t pointerId) override;
+
+protected:
+    struct Movement {
+        nsecs_t eventTime;
+        float position;
+    };
+
+    // Number of samples to keep.
+    // If different strategies would like to maintain different history size, we can make this a
+    // protected const field.
+    static constexpr uint32_t HISTORY_SIZE = 20;
+
+    /**
+     * Duration, in nanoseconds, since the latest movement where a movement may be considered for
+     * velocity calculation.
+     */
+    const nsecs_t mHorizonNanos;
+    /**
+     * If true, data points outside of horizon (see `mHorizonNanos`) will be cleared after each
+     * addition of a new movement.
+     */
+    const bool mMaintainHorizonDuringAdd;
+    std::map<int32_t /*pointerId*/, RingBuffer<Movement>> mMovements;
+};
 
 /*
  * Velocity tracker algorithm based on least-squares linear regression.
  */
-class LeastSquaresVelocityTrackerStrategy : public VelocityTrackerStrategy {
+class LeastSquaresVelocityTrackerStrategy : public AccumulatingVelocityTrackerStrategy {
 public:
     enum class Weighting {
         // No weights applied.  All data points are equally reliable.
@@ -193,13 +208,11 @@
         RECENT,
     };
 
-    // Degree must be no greater than Estimator::MAX_DEGREE.
+    // Degree must be no greater than VelocityTracker::MAX_DEGREE.
     LeastSquaresVelocityTrackerStrategy(uint32_t degree, Weighting weighting = Weighting::NONE);
     ~LeastSquaresVelocityTrackerStrategy() override;
 
-    void clearPointer(int32_t pointerId) override;
-    void addMovement(nsecs_t eventTime, int32_t pointerId, float position) override;
-    std::optional<VelocityTracker::Estimator> getEstimator(int32_t pointerId) const override;
+    std::optional<float> getVelocity(int32_t pointerId) const override;
 
 private:
     // Sample horizon.
@@ -207,23 +220,19 @@
     // changes in direction.
     static const nsecs_t HORIZON = 100 * 1000000; // 100 ms
 
-    // Number of samples to keep.
-    static const uint32_t HISTORY_SIZE = 20;
-
-    struct Movement {
-        nsecs_t eventTime;
-        float position;
-    };
-
     float chooseWeight(int32_t pointerId, uint32_t index) const;
+    /**
+     * An optimized least-squares solver for degree 2 and no weight (i.e. `Weighting.NONE`).
+     * The provided container of movements shall NOT be empty, and shall have the movements in
+     * chronological order.
+     */
+    std::optional<float> solveUnweightedLeastSquaresDeg2(
+            const RingBuffer<Movement>& movements) const;
 
     const uint32_t mDegree;
     const Weighting mWeighting;
-    std::map<int32_t /*pointerId*/, size_t /*positionInArray*/> mIndex;
-    std::map<int32_t /*pointerId*/, std::array<Movement, HISTORY_SIZE>> mMovements;
 };
 
-
 /*
  * Velocity tracker algorithm that uses an IIR filter.
  */
@@ -235,7 +244,7 @@
 
     void clearPointer(int32_t pointerId) override;
     void addMovement(nsecs_t eventTime, int32_t pointerId, float positions) override;
-    std::optional<VelocityTracker::Estimator> getEstimator(int32_t pointerId) const override;
+    std::optional<float> getVelocity(int32_t pointerId) const override;
 
 private:
     // Current state estimate for a particular pointer.
@@ -252,49 +261,33 @@
 
     void initState(State& state, nsecs_t eventTime, float pos) const;
     void updateState(State& state, nsecs_t eventTime, float pos) const;
-    void populateEstimator(const State& state, VelocityTracker::Estimator* outEstimator) const;
 };
 
 
 /*
  * Velocity tracker strategy used prior to ICS.
  */
-class LegacyVelocityTrackerStrategy : public VelocityTrackerStrategy {
+class LegacyVelocityTrackerStrategy : public AccumulatingVelocityTrackerStrategy {
 public:
     LegacyVelocityTrackerStrategy();
     ~LegacyVelocityTrackerStrategy() override;
 
-    void clearPointer(int32_t pointerId) override;
-    void addMovement(nsecs_t eventTime, int32_t pointerId, float position) override;
-    std::optional<VelocityTracker::Estimator> getEstimator(int32_t pointerId) const override;
+    std::optional<float> getVelocity(int32_t pointerId) const override;
 
 private:
     // Oldest sample to consider when calculating the velocity.
     static const nsecs_t HORIZON = 200 * 1000000; // 100 ms
 
-    // Number of samples to keep.
-    static const uint32_t HISTORY_SIZE = 20;
-
     // The minimum duration between samples when estimating velocity.
     static const nsecs_t MIN_DURATION = 10 * 1000000; // 10 ms
-
-    struct Movement {
-        nsecs_t eventTime;
-        float position;
-    };
-
-    std::map<int32_t /*pointerId*/, size_t /*positionInArray*/> mIndex;
-    std::map<int32_t /*pointerId*/, std::array<Movement, HISTORY_SIZE>> mMovements;
 };
 
-class ImpulseVelocityTrackerStrategy : public VelocityTrackerStrategy {
+class ImpulseVelocityTrackerStrategy : public AccumulatingVelocityTrackerStrategy {
 public:
     ImpulseVelocityTrackerStrategy(bool deltaValues);
     ~ImpulseVelocityTrackerStrategy() override;
 
-    void clearPointer(int32_t pointerId) override;
-    void addMovement(nsecs_t eventTime, int32_t pointerId, float position) override;
-    std::optional<VelocityTracker::Estimator> getEstimator(int32_t pointerId) const override;
+    std::optional<float> getVelocity(int32_t pointerId) const override;
 
 private:
     // Sample horizon.
@@ -302,21 +295,10 @@
     // 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;
-        float position;
-    };
-
     // Whether or not the input movement values for the strategy come in the form of delta values.
     // If the input values are not deltas, the strategy needs to calculate deltas as part of its
     // velocity calculation.
     const bool mDeltaValues;
-
-    std::map<int32_t /*pointerId*/, size_t /*positionInArray*/> mIndex;
-    std::map<int32_t /*pointerId*/, std::array<Movement, HISTORY_SIZE>> mMovements;
 };
 
 } // namespace android
diff --git a/include/private/performance_hint_private.h b/include/private/performance_hint_private.h
index eaf3b5e..d50c5f8 100644
--- a/include/private/performance_hint_private.h
+++ b/include/private/performance_hint_private.h
@@ -17,6 +17,8 @@
 #ifndef ANDROID_PRIVATE_NATIVE_PERFORMANCE_HINT_PRIVATE_H
 #define ANDROID_PRIVATE_NATIVE_PERFORMANCE_HINT_PRIVATE_H
 
+#include <stdint.h>
+
 __BEGIN_DECLS
 
 /**
@@ -27,7 +29,7 @@
 /**
  * Hints for the session used to signal upcoming changes in the mode or workload.
  */
-enum SessionHint {
+enum SessionHint: int32_t {
     /**
      * This hint indicates a sudden increase in CPU workload intensity. It means
      * that this hint session needs extra CPU resources immediately to meet the
@@ -61,7 +63,7 @@
  * @return 0 on success
  *         EPIPE if communication with the system service has failed.
  */
-int APerformanceHint_sendHint(void* session, int hint);
+int APerformanceHint_sendHint(void* session, SessionHint hint);
 
 /**
  * Return the list of thread ids, this API should only be used for testing only.
diff --git a/libs/gui/include/gui/JankInfo.h b/libs/gui/include/gui/JankInfo.h
index 1dddeba..bf354e7 100644
--- a/libs/gui/include/gui/JankInfo.h
+++ b/libs/gui/include/gui/JankInfo.h
@@ -46,6 +46,8 @@
     // where the previous frame was presented in the current frame's expected vsync. This pushes the
     // current frame to the next vsync. The behavior is similar to BufferStuffing.
     SurfaceFlingerStuffing = 0x100,
+    // Frame was dropped, as a newer frame was ready and replaced this frame.
+    Dropped = 0x200,
 };
 
 } // namespace android
diff --git a/libs/input/InputEventLabels.cpp b/libs/input/InputEventLabels.cpp
index 4a19227..f99a7d6 100644
--- a/libs/input/InputEventLabels.cpp
+++ b/libs/input/InputEventLabels.cpp
@@ -343,7 +343,11 @@
     DEFINE_KEYCODE(STYLUS_BUTTON_SECONDARY), \
     DEFINE_KEYCODE(STYLUS_BUTTON_TERTIARY), \
     DEFINE_KEYCODE(STYLUS_BUTTON_TAIL), \
-    DEFINE_KEYCODE(RECENT_APPS)
+    DEFINE_KEYCODE(RECENT_APPS), \
+    DEFINE_KEYCODE(MACRO_1), \
+    DEFINE_KEYCODE(MACRO_2), \
+    DEFINE_KEYCODE(MACRO_3), \
+    DEFINE_KEYCODE(MACRO_4)
 
 // NOTE: If you add a new axis here you must also add it to several other files.
 //       Refer to frameworks/base/core/java/android/view/MotionEvent.java for the full list.
diff --git a/libs/input/MotionPredictor.cpp b/libs/input/MotionPredictor.cpp
index b4151c6..0d4213c 100644
--- a/libs/input/MotionPredictor.cpp
+++ b/libs/input/MotionPredictor.cpp
@@ -25,9 +25,9 @@
 #include <string>
 #include <vector>
 
+#include <android-base/logging.h>
 #include <android-base/strings.h>
 #include <android/input.h>
-#include <log/log.h>
 
 #include <attestation/HmacKeyManager.h>
 #include <input/TfLiteMotionPredictor.h>
diff --git a/libs/input/VelocityControl.cpp b/libs/input/VelocityControl.cpp
index 5720099..c835a08 100644
--- a/libs/input/VelocityControl.cpp
+++ b/libs/input/VelocityControl.cpp
@@ -37,7 +37,7 @@
     reset();
 }
 
-VelocityControlParameters& VelocityControl::getParameters() {
+const VelocityControlParameters& VelocityControl::getParameters() const{
     return mParameters;
 }
 
diff --git a/libs/input/VelocityTracker.cpp b/libs/input/VelocityTracker.cpp
index 8551e5f..87c7768 100644
--- a/libs/input/VelocityTracker.cpp
+++ b/libs/input/VelocityTracker.cpp
@@ -22,7 +22,6 @@
 #include <math.h>
 #include <optional>
 
-#include <android-base/stringprintf.h>
 #include <input/PrintTools.h>
 #include <input/VelocityTracker.h>
 #include <utils/BitSet.h>
@@ -56,6 +55,9 @@
 // Nanoseconds per milliseconds.
 static const nsecs_t NANOS_PER_MS = 1000000;
 
+// Seconds per nanosecond.
+static const float SECONDS_PER_NANO = 1E-9;
+
 // All axes supported for velocity tracking, mapped to their default strategies.
 // Although other strategies are available for testing and comparison purposes,
 // the default strategy is the one that applications will actually use.  Be very careful
@@ -268,12 +270,8 @@
               ", activePointerId=%s",
               eventTime, pointerId, toString(mActivePointerId).c_str());
 
-        std::optional<Estimator> estimator = getEstimator(axis, pointerId);
-        ALOGD("  %d: axis=%d, position=%0.3f, "
-              "estimator (degree=%d, coeff=%s, confidence=%f)",
-              pointerId, axis, position, int((*estimator).degree),
-              vectorToString((*estimator).coeff.data(), (*estimator).degree + 1).c_str(),
-              (*estimator).confidence);
+        ALOGD("  %d: axis=%d, position=%0.3f, velocity=%s", pointerId, axis, position,
+              toString(getVelocity(axis, pointerId)).c_str());
     }
 }
 
@@ -349,9 +347,9 @@
 }
 
 std::optional<float> VelocityTracker::getVelocity(int32_t axis, int32_t pointerId) const {
-    std::optional<Estimator> estimator = getEstimator(axis, pointerId);
-    if (estimator && (*estimator).degree >= 1) {
-        return (*estimator).coeff[1];
+    const auto& it = mConfiguredStrategies.find(axis);
+    if (it != mConfiguredStrategies.end()) {
+        return it->second->getVelocity(pointerId);
     }
     return {};
 }
@@ -374,56 +372,52 @@
     return computedVelocity;
 }
 
-std::optional<VelocityTracker::Estimator> VelocityTracker::getEstimator(int32_t axis,
-                                                                        int32_t pointerId) const {
-    const auto& it = mConfiguredStrategies.find(axis);
-    if (it == mConfiguredStrategies.end()) {
-        return std::nullopt;
+AccumulatingVelocityTrackerStrategy::AccumulatingVelocityTrackerStrategy(
+        nsecs_t horizonNanos, bool maintainHorizonDuringAdd)
+      : mHorizonNanos(horizonNanos), mMaintainHorizonDuringAdd(maintainHorizonDuringAdd) {}
+
+void AccumulatingVelocityTrackerStrategy::clearPointer(int32_t pointerId) {
+    mMovements.erase(pointerId);
+}
+
+void AccumulatingVelocityTrackerStrategy::addMovement(nsecs_t eventTime, int32_t pointerId,
+                                                      float position) {
+    auto [ringBufferIt, _] = mMovements.try_emplace(pointerId, HISTORY_SIZE);
+    RingBuffer<Movement>& movements = ringBufferIt->second;
+    const size_t size = movements.size();
+
+    if (size != 0 && movements[size - 1].eventTime == eventTime) {
+        // When ACTION_POINTER_DOWN happens, we will first receive ACTION_MOVE with the coordinates
+        // of the existing pointers, and then ACTION_POINTER_DOWN with the coordinates that include
+        // the new pointer. If the eventtimes for both events are identical, just update the data
+        // for this time (i.e. pop out the last element, and insert the updated movement).
+        // We only compare against the last value, as it is likely that addMovement is called
+        // in chronological order as events occur.
+        movements.popBack();
     }
-    return it->second->getEstimator(pointerId);
+
+    movements.pushBack({eventTime, position});
+
+    // Clear movements that do not fall within `mHorizonNanos` of the latest movement.
+    // Note that, if in the future we decide to use more movements (i.e. increase HISTORY_SIZE),
+    // we can consider making this step binary-search based, which will give us some improvement.
+    if (mMaintainHorizonDuringAdd) {
+        while (eventTime - movements[0].eventTime > mHorizonNanos) {
+            movements.popFront();
+        }
+    }
 }
 
 // --- LeastSquaresVelocityTrackerStrategy ---
 
 LeastSquaresVelocityTrackerStrategy::LeastSquaresVelocityTrackerStrategy(uint32_t degree,
                                                                          Weighting weighting)
-      : mDegree(degree), mWeighting(weighting) {}
+      : AccumulatingVelocityTrackerStrategy(HORIZON /*horizonNanos*/,
+                                            true /*maintainHorizonDuringAdd*/),
+        mDegree(degree),
+        mWeighting(weighting) {}
 
-LeastSquaresVelocityTrackerStrategy::~LeastSquaresVelocityTrackerStrategy() {
-}
-
-void LeastSquaresVelocityTrackerStrategy::clearPointer(int32_t pointerId) {
-    mIndex.erase(pointerId);
-    mMovements.erase(pointerId);
-}
-
-void LeastSquaresVelocityTrackerStrategy::addMovement(nsecs_t eventTime, int32_t pointerId,
-                                                      float position) {
-    // If data for this pointer already exists, we have a valid entry at the position of
-    // mIndex[pointerId] and mMovements[pointerId]. In that case, we need to advance the index
-    // to the next position in the circular buffer and write the new Movement there. Otherwise,
-    // if this is a first movement for this pointer, we initialize the maps mIndex and mMovements
-    // for this pointer and write to the first position.
-    auto [movementIt, inserted] = mMovements.insert({pointerId, {}});
-    auto [indexIt, _] = mIndex.insert({pointerId, 0});
-    size_t& index = indexIt->second;
-    if (!inserted && movementIt->second[index].eventTime != eventTime) {
-        // When ACTION_POINTER_DOWN happens, we will first receive ACTION_MOVE with the coordinates
-        // of the existing pointers, and then ACTION_POINTER_DOWN with the coordinates that include
-        // the new pointer. If the eventtimes for both events are identical, just update the data
-        // for this time.
-        // We only compare against the last value, as it is likely that addMovement is called
-        // in chronological order as events occur.
-        index++;
-    }
-    if (index == HISTORY_SIZE) {
-        index = 0;
-    }
-
-    Movement& movement = movementIt->second[index];
-    movement.eventTime = eventTime;
-    movement.position = position;
-}
+LeastSquaresVelocityTrackerStrategy::~LeastSquaresVelocityTrackerStrategy() {}
 
 /**
  * Solves a linear least squares problem to obtain a N degree polynomial that fits
@@ -474,10 +468,9 @@
  * http://en.wikipedia.org/wiki/Numerical_methods_for_linear_least_squares
  * http://en.wikipedia.org/wiki/Gram-Schmidt
  */
-static bool solveLeastSquares(const std::vector<float>& x, const std::vector<float>& y,
-                              const std::vector<float>& w, uint32_t n,
-                              std::array<float, VelocityTracker::Estimator::MAX_DEGREE + 1>& outB,
-                              float* outDet) {
+static std::optional<float> solveLeastSquares(const std::vector<float>& x,
+                                              const std::vector<float>& y,
+                                              const std::vector<float>& w, uint32_t n) {
     const size_t m = x.size();
 
     ALOGD_IF(DEBUG_STRATEGY, "solveLeastSquares: m=%d, n=%d, x=%s, y=%s, w=%s", int(m), int(n),
@@ -515,7 +508,7 @@
         if (norm < 0.000001f) {
             // vectors are linearly dependent or zero so no solution
             ALOGD_IF(DEBUG_STRATEGY, "  - no solution, norm=%f", norm);
-            return false;
+            return {};
         }
 
         float invNorm = 1.0f / norm;
@@ -549,6 +542,7 @@
     for (uint32_t h = 0; h < m; h++) {
         wy[h] = y[h] * w[h];
     }
+    std::array<float, VelocityTracker::MAX_DEGREE + 1> outB;
     for (uint32_t i = n; i != 0; ) {
         i--;
         outB[i] = vectorDot(&q[i][0], wy, m);
@@ -570,42 +564,46 @@
     }
     ymean /= m;
 
-    float sserr = 0;
-    float sstot = 0;
-    for (uint32_t h = 0; h < m; h++) {
-        float err = y[h] - outB[0];
-        float term = 1;
-        for (uint32_t i = 1; i < n; i++) {
-            term *= x[h];
-            err -= term * outB[i];
+    if (DEBUG_STRATEGY) {
+        float sserr = 0;
+        float sstot = 0;
+        for (uint32_t h = 0; h < m; h++) {
+            float err = y[h] - outB[0];
+            float term = 1;
+            for (uint32_t i = 1; i < n; i++) {
+                term *= x[h];
+                err -= term * outB[i];
+            }
+            sserr += w[h] * w[h] * err * err;
+            float var = y[h] - ymean;
+            sstot += w[h] * w[h] * var * var;
         }
-        sserr += w[h] * w[h] * err * err;
-        float var = y[h] - ymean;
-        sstot += w[h] * w[h] * var * var;
+        ALOGD("  - sserr=%f", sserr);
+        ALOGD("  - sstot=%f", sstot);
     }
-    *outDet = sstot > 0.000001f ? 1.0f - (sserr / sstot) : 1;
 
-    ALOGD_IF(DEBUG_STRATEGY, "  - sserr=%f", sserr);
-    ALOGD_IF(DEBUG_STRATEGY, "  - sstot=%f", sstot);
-    ALOGD_IF(DEBUG_STRATEGY, "  - det=%f", *outDet);
-
-    return true;
+    return outB[1];
 }
 
 /*
  * Optimized unweighted second-order least squares fit. About 2x speed improvement compared to
  * the default implementation
  */
-static std::optional<std::array<float, 3>> solveUnweightedLeastSquaresDeg2(
-        const std::vector<float>& x, const std::vector<float>& y) {
-    const size_t count = x.size();
-    LOG_ALWAYS_FATAL_IF(count != y.size(), "Mismatching array sizes");
-    // Solving y = a*x^2 + b*x + c
+std::optional<float> LeastSquaresVelocityTrackerStrategy::solveUnweightedLeastSquaresDeg2(
+        const RingBuffer<Movement>& movements) const {
+    // Solving y = a*x^2 + b*x + c, where
+    //      - "x" is age (i.e. duration since latest movement) of the movemnets
+    //      - "y" is positions of the movements.
     float sxi = 0, sxiyi = 0, syi = 0, sxi2 = 0, sxi3 = 0, sxi2yi = 0, sxi4 = 0;
 
+    const size_t count = movements.size();
+    const Movement& newestMovement = movements[count - 1];
     for (size_t i = 0; i < count; i++) {
-        float xi = x[i];
-        float yi = y[i];
+        const Movement& movement = movements[i];
+        nsecs_t age = newestMovement.eventTime - movement.eventTime;
+        float xi = -age * SECONDS_PER_NANO;
+        float yi = movement.position;
+
         float xi2 = xi*xi;
         float xi3 = xi2*xi;
         float xi4 = xi3*xi;
@@ -632,124 +630,68 @@
         ALOGW("division by 0 when computing velocity, Sxx=%f, Sx2x2=%f, Sxx2=%f", Sxx, Sx2x2, Sxx2);
         return std::nullopt;
     }
-    // Compute a
-    float numerator = Sx2y*Sxx - Sxy*Sxx2;
-    float a = numerator / denominator;
 
-    // Compute b
-    numerator = Sxy*Sx2x2 - Sx2y*Sxx2;
-    float b = numerator / denominator;
-
-    // Compute c
-    float c = syi/count - b * sxi/count - a * sxi2/count;
-
-    return std::make_optional(std::array<float, 3>({c, b, a}));
+    return (Sxy * Sx2x2 - Sx2y * Sxx2) / denominator;
 }
 
-std::optional<VelocityTracker::Estimator> LeastSquaresVelocityTrackerStrategy::getEstimator(
-        int32_t pointerId) const {
+std::optional<float> LeastSquaresVelocityTrackerStrategy::getVelocity(int32_t pointerId) const {
     const auto movementIt = mMovements.find(pointerId);
     if (movementIt == mMovements.end()) {
         return std::nullopt; // no data
     }
+
+    const RingBuffer<Movement>& movements = movementIt->second;
+    const size_t size = movements.size();
+    if (size == 0) {
+        return std::nullopt; // no data
+    }
+
+    uint32_t degree = mDegree;
+    if (degree > size - 1) {
+        degree = size - 1;
+    }
+
+    if (degree <= 0) {
+        return std::nullopt;
+    }
+
+    if (degree == 2 && mWeighting == Weighting::NONE) {
+        // Optimize unweighted, quadratic polynomial fit
+        return solveUnweightedLeastSquaresDeg2(movements);
+    }
+
     // Iterate over movement samples in reverse time order and collect samples.
     std::vector<float> positions;
     std::vector<float> w;
     std::vector<float> time;
 
-    uint32_t index = mIndex.at(pointerId);
-    const Movement& newestMovement = movementIt->second[index];
-    do {
-        const Movement& movement = movementIt->second[index];
-
+    const Movement& newestMovement = movements[size - 1];
+    for (ssize_t i = size - 1; i >= 0; i--) {
+        const Movement& movement = movements[i];
         nsecs_t age = newestMovement.eventTime - movement.eventTime;
-        if (age > HORIZON) {
-            break;
-        }
-        if (movement.eventTime == 0 && index != 0) {
-            // All eventTime's are initialized to 0. In this fixed-width circular buffer, it's
-            // possible that not all entries are valid. We use a time=0 as a signal for those
-            // uninitialized values. If we encounter a time of 0 in a position
-            // that's > 0, it means that we hit the block where the data wasn't initialized.
-            // We still don't know whether the value at index=0, with eventTime=0 is valid.
-            // However, that's only possible when the value is by itself. So there's no hard in
-            // processing it anyways, since the velocity for a single point is zero, and this
-            // situation will only be encountered in artificial circumstances (in tests).
-            // In practice, time will never be 0.
-            break;
-        }
         positions.push_back(movement.position);
-        w.push_back(chooseWeight(pointerId, index));
+        w.push_back(chooseWeight(pointerId, i));
         time.push_back(-age * 0.000000001f);
-        index = (index == 0 ? HISTORY_SIZE : index) - 1;
-    } while (positions.size() < HISTORY_SIZE);
-
-    const size_t m = positions.size();
-    if (m == 0) {
-        return std::nullopt; // no data
     }
 
-    // Calculate a least squares polynomial fit.
-    uint32_t degree = mDegree;
-    if (degree > m - 1) {
-        degree = m - 1;
-    }
-
-    if (degree == 2 && mWeighting == Weighting::NONE) {
-        // Optimize unweighted, quadratic polynomial fit
-        std::optional<std::array<float, 3>> coeff =
-                solveUnweightedLeastSquaresDeg2(time, positions);
-        if (coeff) {
-            VelocityTracker::Estimator estimator;
-            estimator.time = newestMovement.eventTime;
-            estimator.degree = 2;
-            estimator.confidence = 1;
-            for (size_t i = 0; i <= estimator.degree; i++) {
-                estimator.coeff[i] = (*coeff)[i];
-            }
-            return estimator;
-        }
-    } else if (degree >= 1) {
-        // General case for an Nth degree polynomial fit
-        float det;
-        uint32_t n = degree + 1;
-        VelocityTracker::Estimator estimator;
-        if (solveLeastSquares(time, positions, w, n, estimator.coeff, &det)) {
-            estimator.time = newestMovement.eventTime;
-            estimator.degree = degree;
-            estimator.confidence = det;
-
-            ALOGD_IF(DEBUG_STRATEGY, "estimate: degree=%d, coeff=%s, confidence=%f",
-                     int(estimator.degree), vectorToString(estimator.coeff.data(), n).c_str(),
-                     estimator.confidence);
-
-            return estimator;
-        }
-    }
-
-    // No velocity data available for this pointer, but we do have its current position.
-    VelocityTracker::Estimator estimator;
-    estimator.coeff[0] = positions[0];
-    estimator.time = newestMovement.eventTime;
-    estimator.degree = 0;
-    estimator.confidence = 1;
-    return estimator;
+    // General case for an Nth degree polynomial fit
+    return solveLeastSquares(time, positions, w, degree + 1);
 }
 
 float LeastSquaresVelocityTrackerStrategy::chooseWeight(int32_t pointerId, uint32_t index) const {
-    const std::array<Movement, HISTORY_SIZE>& movements = mMovements.at(pointerId);
+    const RingBuffer<Movement>& movements = mMovements.at(pointerId);
+    const size_t size = movements.size();
     switch (mWeighting) {
         case Weighting::DELTA: {
             // Weight points based on how much time elapsed between them and the next
             // point so that points that "cover" a shorter time span are weighed less.
             //   delta  0ms: 0.5
             //   delta 10ms: 1.0
-            if (index == mIndex.at(pointerId)) {
+            if (index == size - 1) {
                 return 1.0f;
             }
-            uint32_t nextIndex = (index + 1) % HISTORY_SIZE;
             float deltaMillis =
-                    (movements[nextIndex].eventTime - movements[index].eventTime) * 0.000001f;
+                    (movements[index + 1].eventTime - movements[index].eventTime) * 0.000001f;
             if (deltaMillis < 0) {
                 return 0.5f;
             }
@@ -766,8 +708,7 @@
             //   age 50ms: 1.0
             //   age 60ms: 0.5
             float ageMillis =
-                    (movements[mIndex.at(pointerId)].eventTime - movements[index].eventTime) *
-                    0.000001f;
+                    (movements[size - 1].eventTime - movements[index].eventTime) * 0.000001f;
             if (ageMillis < 0) {
                 return 0.5f;
             }
@@ -789,8 +730,7 @@
             //   age  50ms: 1.0
             //   age 100ms: 0.5
             float ageMillis =
-                    (movements[mIndex.at(pointerId)].eventTime - movements[index].eventTime) *
-                    0.000001f;
+                    (movements[size - 1].eventTime - movements[index].eventTime) * 0.000001f;
             if (ageMillis < 50) {
                 return 1.0f;
             }
@@ -830,13 +770,9 @@
     mPointerIdBits.markBit(pointerId);
 }
 
-std::optional<VelocityTracker::Estimator> IntegratingVelocityTrackerStrategy::getEstimator(
-        int32_t pointerId) const {
+std::optional<float> IntegratingVelocityTrackerStrategy::getVelocity(int32_t pointerId) const {
     if (mPointerIdBits.hasBit(pointerId)) {
-        const State& state = mPointerState[pointerId];
-        VelocityTracker::Estimator estimator;
-        populateEstimator(state, &estimator);
-        return estimator;
+        return mPointerState[pointerId].vel;
     }
 
     return std::nullopt;
@@ -886,77 +822,39 @@
     state.pos = pos;
 }
 
-void IntegratingVelocityTrackerStrategy::populateEstimator(const State& state,
-        VelocityTracker::Estimator* outEstimator) const {
-    outEstimator->time = state.updateTime;
-    outEstimator->confidence = 1.0f;
-    outEstimator->degree = state.degree;
-    outEstimator->coeff[0] = state.pos;
-    outEstimator->coeff[1] = state.vel;
-    outEstimator->coeff[2] = state.accel / 2;
-}
-
-
 // --- LegacyVelocityTrackerStrategy ---
 
-LegacyVelocityTrackerStrategy::LegacyVelocityTrackerStrategy() {}
+LegacyVelocityTrackerStrategy::LegacyVelocityTrackerStrategy()
+      : AccumulatingVelocityTrackerStrategy(HORIZON /*horizonNanos*/,
+                                            false /*maintainHorizonDuringAdd*/) {}
 
 LegacyVelocityTrackerStrategy::~LegacyVelocityTrackerStrategy() {
 }
 
-void LegacyVelocityTrackerStrategy::clearPointer(int32_t pointerId) {
-    mIndex.erase(pointerId);
-    mMovements.erase(pointerId);
-}
-
-void LegacyVelocityTrackerStrategy::addMovement(nsecs_t eventTime, int32_t pointerId,
-                                                float position) {
-    // If data for this pointer already exists, we have a valid entry at the position of
-    // mIndex[pointerId] and mMovements[pointerId]. In that case, we need to advance the index
-    // to the next position in the circular buffer and write the new Movement there. Otherwise,
-    // if this is a first movement for this pointer, we initialize the maps mIndex and mMovements
-    // for this pointer and write to the first position.
-    auto [movementIt, inserted] = mMovements.insert({pointerId, {}});
-    auto [indexIt, _] = mIndex.insert({pointerId, 0});
-    size_t& index = indexIt->second;
-    if (!inserted && movementIt->second[index].eventTime != eventTime) {
-        // When ACTION_POINTER_DOWN happens, we will first receive ACTION_MOVE with the coordinates
-        // of the existing pointers, and then ACTION_POINTER_DOWN with the coordinates that include
-        // the new pointer. If the eventtimes for both events are identical, just update the data
-        // for this time.
-        // We only compare against the last value, as it is likely that addMovement is called
-        // in chronological order as events occur.
-        index++;
-    }
-    if (index == HISTORY_SIZE) {
-        index = 0;
-    }
-
-    Movement& movement = movementIt->second[index];
-    movement.eventTime = eventTime;
-    movement.position = position;
-}
-
-std::optional<VelocityTracker::Estimator> LegacyVelocityTrackerStrategy::getEstimator(
-        int32_t pointerId) const {
+std::optional<float> LegacyVelocityTrackerStrategy::getVelocity(int32_t pointerId) const {
     const auto movementIt = mMovements.find(pointerId);
     if (movementIt == mMovements.end()) {
         return std::nullopt; // no data
     }
-    const Movement& newestMovement = movementIt->second[mIndex.at(pointerId)];
+
+    const RingBuffer<Movement>& movements = movementIt->second;
+    const size_t size = movements.size();
+    if (size == 0) {
+        return std::nullopt; // no data
+    }
+
+    const Movement& newestMovement = movements[size - 1];
 
     // Find the oldest sample that contains the pointer and that is not older than HORIZON.
     nsecs_t minTime = newestMovement.eventTime - HORIZON;
-    uint32_t oldestIndex = mIndex.at(pointerId);
-    uint32_t numTouches = 1;
-    do {
-        uint32_t nextOldestIndex = (oldestIndex == 0 ? HISTORY_SIZE : oldestIndex) - 1;
-        const Movement& nextOldestMovement = mMovements.at(pointerId)[nextOldestIndex];
+    uint32_t oldestIndex = size - 1;
+    for (ssize_t i = size - 1; i >= 0; i--) {
+        const Movement& nextOldestMovement = movements[i];
         if (nextOldestMovement.eventTime < minTime) {
             break;
         }
-        oldestIndex = nextOldestIndex;
-    } while (++numTouches < HISTORY_SIZE);
+        oldestIndex = i;
+    }
 
     // Calculate an exponentially weighted moving average of the velocity estimate
     // at different points in time measured relative to the oldest sample.
@@ -970,17 +868,13 @@
     // 16ms apart but some consecutive samples could be only 0.5sm apart because
     // the hardware or driver reports them irregularly or in bursts.
     float accumV = 0;
-    uint32_t index = oldestIndex;
     uint32_t samplesUsed = 0;
-    const Movement& oldestMovement = mMovements.at(pointerId)[oldestIndex];
+    const Movement& oldestMovement = movements[oldestIndex];
     float oldestPosition = oldestMovement.position;
     nsecs_t lastDuration = 0;
 
-    while (numTouches-- > 1) {
-        if (++index == HISTORY_SIZE) {
-            index = 0;
-        }
-        const Movement& movement = mMovements.at(pointerId)[index];
+    for (size_t i = oldestIndex; i < size; i++) {
+        const Movement& movement = movements[i];
         nsecs_t duration = movement.eventTime - oldestMovement.eventTime;
 
         // If the duration between samples is small, we may significantly overestimate
@@ -996,62 +890,22 @@
         }
     }
 
-    // Report velocity.
-    float newestPosition = newestMovement.position;
-    VelocityTracker::Estimator estimator;
-    estimator.time = newestMovement.eventTime;
-    estimator.confidence = 1;
-    estimator.coeff[0] = newestPosition;
     if (samplesUsed) {
-        estimator.coeff[1] = accumV;
-        estimator.degree = 1;
-    } else {
-        estimator.degree = 0;
+        return accumV;
     }
-    return estimator;
+    return std::nullopt;
 }
 
 // --- ImpulseVelocityTrackerStrategy ---
 
 ImpulseVelocityTrackerStrategy::ImpulseVelocityTrackerStrategy(bool deltaValues)
-      : mDeltaValues(deltaValues) {}
+      : AccumulatingVelocityTrackerStrategy(HORIZON /*horizonNanos*/,
+                                            true /*maintainHorizonDuringAdd*/),
+        mDeltaValues(deltaValues) {}
 
 ImpulseVelocityTrackerStrategy::~ImpulseVelocityTrackerStrategy() {
 }
 
-void ImpulseVelocityTrackerStrategy::clearPointer(int32_t pointerId) {
-    mIndex.erase(pointerId);
-    mMovements.erase(pointerId);
-}
-
-void ImpulseVelocityTrackerStrategy::addMovement(nsecs_t eventTime, int32_t pointerId,
-                                                 float position) {
-    // If data for this pointer already exists, we have a valid entry at the position of
-    // mIndex[pointerId] and mMovements[pointerId]. In that case, we need to advance the index
-    // to the next position in the circular buffer and write the new Movement there. Otherwise,
-    // if this is a first movement for this pointer, we initialize the maps mIndex and mMovements
-    // for this pointer and write to the first position.
-    auto [movementIt, inserted] = mMovements.insert({pointerId, {}});
-    auto [indexIt, _] = mIndex.insert({pointerId, 0});
-    size_t& index = indexIt->second;
-    if (!inserted && movementIt->second[index].eventTime != eventTime) {
-        // When ACTION_POINTER_DOWN happens, we will first receive ACTION_MOVE with the coordinates
-        // of the existing pointers, and then ACTION_POINTER_DOWN with the coordinates that include
-        // the new pointer. If the eventtimes for both events are identical, just update the data
-        // for this time.
-        // We only compare against the last value, as it is likely that addMovement is called
-        // in chronological order as events occur.
-        index++;
-    }
-    if (index == HISTORY_SIZE) {
-        index = 0;
-    }
-
-    Movement& movement = movementIt->second[index];
-    movement.eventTime = eventTime;
-    movement.position = position;
-}
-
 /**
  * Calculate the total impulse provided to the screen and the resulting velocity.
  *
@@ -1126,112 +980,44 @@
     return (work < 0 ? -1.0 : 1.0) * sqrtf(fabsf(work)) * sqrt2;
 }
 
-static float calculateImpulseVelocity(const nsecs_t* t, const float* x, size_t count,
-                                      bool deltaValues) {
-    // 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 SECONDS_PER_NANO = 1E-9;
-
-    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 the data values are delta values, we do not have to calculate deltas here.
-    // We can use the delta values directly, along with the calculated time deltas.
-    // Since the data value input is in reversed time order:
-    //      [a] for non-delta inputs, instantenous velocity = (x[i] - x[i-1])/(t[i] - t[i-1])
-    //      [b] for delta inputs, instantenous velocity = -x[i-1]/(t[i] - t[i - 1])
-    // e.g., let the non-delta values are: V = [2, 3, 7], the equivalent deltas are D = [2, 1, 4].
-    // Since the input is in reversed time order, the input values for this function would be
-    // V'=[7, 3, 2] and D'=[4, 1, 2] for the non-delta and delta values, respectively.
-    //
-    // The equivalent of {(V'[2] - V'[1]) = 2 - 3 = -1} would be {-D'[1] = -1}
-    // Similarly, the equivalent of {(V'[1] - V'[0]) = 3 - 7 = -4} would be {-D'[0] = -4}
-
-    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;
-        }
-        const float deltaX = deltaValues ? -x[0] : x[1] - x[0];
-        return deltaX / (SECONDS_PER_NANO * (t[1] - t[0]));
-    }
-    // Guaranteed to have at least 3 points here
-    float work = 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;
-        }
-        float vprev = kineticEnergyToVelocity(work); // v[i-1]
-        const float deltaX = deltaValues ? -x[i-1] : x[i] - x[i-1];
-        float vcurr = deltaX / (SECONDS_PER_NANO * (t[i] - t[i-1])); // v[i]
-        work += (vcurr - vprev) * fabsf(vcurr);
-        if (i == count - 1) {
-            work *= 0.5; // initial condition, case 2) above
-        }
-    }
-    return kineticEnergyToVelocity(work);
-}
-
-std::optional<VelocityTracker::Estimator> ImpulseVelocityTrackerStrategy::getEstimator(
-        int32_t pointerId) const {
+std::optional<float> ImpulseVelocityTrackerStrategy::getVelocity(int32_t pointerId) const {
     const auto movementIt = mMovements.find(pointerId);
     if (movementIt == mMovements.end()) {
         return std::nullopt; // no data
     }
 
-    // Iterate over movement samples in reverse time order and collect samples.
-    float positions[HISTORY_SIZE];
-    nsecs_t time[HISTORY_SIZE];
-    size_t m = 0; // number of points that will be used for fitting
-    size_t index = mIndex.at(pointerId);
-    const Movement& newestMovement = movementIt->second[index];
-    do {
-        const Movement& movement = movementIt->second[index];
-
-        nsecs_t age = newestMovement.eventTime - movement.eventTime;
-        if (age > HORIZON) {
-            break;
-        }
-        if (movement.eventTime == 0 && index != 0) {
-            // All eventTime's are initialized to 0. If we encounter a time of 0 in a position
-            // that's >0, it means that we hit the block where the data wasn't initialized.
-            // It's also possible that the sample at 0 would be invalid, but there's no harm in
-            // processing it, since it would be just a single point, and will only be encountered
-            // in artificial circumstances (in tests).
-            break;
-        }
-
-        positions[m] = movement.position;
-        time[m] = movement.eventTime;
-        index = (index == 0 ? HISTORY_SIZE : index) - 1;
-    } while (++m < HISTORY_SIZE);
-
-    if (m == 0) {
+    const RingBuffer<Movement>& movements = movementIt->second;
+    const size_t size = movements.size();
+    if (size == 0) {
         return std::nullopt; // no data
     }
-    VelocityTracker::Estimator estimator;
-    estimator.coeff[0] = 0;
-    estimator.coeff[1] = calculateImpulseVelocity(time, positions, m, mDeltaValues);
-    estimator.coeff[2] = 0;
 
-    estimator.time = newestMovement.eventTime;
-    estimator.degree = 2; // similar results to 2nd degree fit
-    estimator.confidence = 1;
+    float work = 0;
+    for (size_t i = 0; i < size - 1; i++) {
+        const Movement& mvt = movements[i];
+        const Movement& nextMvt = movements[i + 1];
 
-    ALOGD_IF(DEBUG_STRATEGY, "velocity: %.1f", estimator.coeff[1]);
+        float vprev = kineticEnergyToVelocity(work);
+        float delta = mDeltaValues ? nextMvt.position : nextMvt.position - mvt.position;
+        float vcurr = delta / (SECONDS_PER_NANO * (nextMvt.eventTime - mvt.eventTime));
+        work += (vcurr - vprev) * fabsf(vcurr);
+
+        if (i == 0) {
+            work *= 0.5; // initial condition, case 2) above
+        }
+    }
+
+    const float velocity = kineticEnergyToVelocity(work);
+    ALOGD_IF(DEBUG_STRATEGY, "velocity: %.1f", velocity);
 
     if (DEBUG_IMPULSE) {
         // TODO(b/134179997): delete this block once the switch to 'impulse' is complete.
         // Calculate the lsq2 velocity for the same inputs to allow runtime comparisons.
         // X axis chosen arbitrarily for velocity comparisons.
         VelocityTracker lsq2(VelocityTracker::Strategy::LSQ2);
-        for (ssize_t i = m - 1; i >= 0; i--) {
-            lsq2.addMovement(time[i], pointerId, AMOTION_EVENT_AXIS_X, positions[i]);
+        for (size_t i = 0; i < size; i++) {
+            const Movement& mvt = movements[i];
+            lsq2.addMovement(mvt.eventTime, pointerId, AMOTION_EVENT_AXIS_X, mvt.position);
         }
         std::optional<float> v = lsq2.getVelocity(AMOTION_EVENT_AXIS_X, pointerId);
         if (v) {
@@ -1240,7 +1026,7 @@
             ALOGD("lsq2 velocity: could not compute velocity");
         }
     }
-    return estimator;
+    return velocity;
 }
 
 } // namespace android
diff --git a/libs/input/tests/VelocityTracker_test.cpp b/libs/input/tests/VelocityTracker_test.cpp
index 0277579..2a424af 100644
--- a/libs/input/tests/VelocityTracker_test.cpp
+++ b/libs/input/tests/VelocityTracker_test.cpp
@@ -42,8 +42,8 @@
 // here EV = expected value, tol = VELOCITY_TOLERANCE
 constexpr float VELOCITY_TOLERANCE = 0.2;
 
-// estimate coefficients must be within 0.001% of the target value
-constexpr float COEFFICIENT_TOLERANCE = 0.00001;
+// quadratic velocity must be within 0.001% of the target value
+constexpr float QUADRATIC_VELOCITY_TOLERANCE = 0.00001;
 
 // --- VelocityTrackerTest ---
 class VelocityTrackerTest : public testing::Test { };
@@ -76,10 +76,6 @@
     }
 }
 
-static void checkCoefficient(float actual, float target) {
-    EXPECT_NEAR_BY_FRACTION(actual, target, COEFFICIENT_TOLERANCE);
-}
-
 struct Position {
     float x;
     float y;
@@ -284,21 +280,20 @@
     checkVelocity(computeVelocity(strategy, motions, AMOTION_EVENT_AXIS_SCROLL), targetVelocity);
 }
 
-static void computeAndCheckQuadraticEstimate(const std::vector<PlanarMotionEventEntry>& motions,
-                                             const std::array<float, 3>& coefficients) {
+static void computeAndCheckQuadraticVelocity(const std::vector<PlanarMotionEventEntry>& motions,
+                                             float velocity) {
     VelocityTracker vt(VelocityTracker::Strategy::LSQ2);
     std::vector<MotionEvent> events = createTouchMotionEventStream(motions);
     for (MotionEvent event : events) {
         vt.addMovement(&event);
     }
-    std::optional<VelocityTracker::Estimator> estimatorX = vt.getEstimator(AMOTION_EVENT_AXIS_X, 0);
-    std::optional<VelocityTracker::Estimator> estimatorY = vt.getEstimator(AMOTION_EVENT_AXIS_Y, 0);
-    EXPECT_TRUE(estimatorX);
-    EXPECT_TRUE(estimatorY);
-    for (size_t i = 0; i< coefficients.size(); i++) {
-        checkCoefficient((*estimatorX).coeff[i], coefficients[i]);
-        checkCoefficient((*estimatorY).coeff[i], coefficients[i]);
-    }
+    std::optional<float> velocityX = vt.getVelocity(AMOTION_EVENT_AXIS_X, 0);
+    std::optional<float> velocityY = vt.getVelocity(AMOTION_EVENT_AXIS_Y, 0);
+    ASSERT_TRUE(velocityX);
+    ASSERT_TRUE(velocityY);
+
+    EXPECT_NEAR_BY_FRACTION(*velocityX, velocity, QUADRATIC_VELOCITY_TOLERANCE);
+    EXPECT_NEAR_BY_FRACTION(*velocityY, velocity, QUADRATIC_VELOCITY_TOLERANCE);
 }
 
 /*
@@ -461,8 +456,6 @@
 
     EXPECT_FALSE(vt.getVelocity(AMOTION_EVENT_AXIS_X, DEFAULT_POINTER_ID));
 
-    EXPECT_FALSE(vt.getEstimator(AMOTION_EVENT_AXIS_X, DEFAULT_POINTER_ID));
-
     VelocityTracker::ComputedVelocity computedVelocity = vt.getComputedVelocity(1000, 1000);
     for (uint32_t id = 0; id <= MAX_POINTER_ID; id++) {
         EXPECT_FALSE(computedVelocity.getVelocity(AMOTION_EVENT_AXIS_X, id));
@@ -1074,7 +1067,7 @@
  * If the events with POINTER_UP or POINTER_DOWN are not handled correctly (these should not be
  * part of the fitted data), this can cause large velocity values to be reported instead.
  */
-TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_ThreeFingerTap) {
+TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategy_ThreeFingerTap) {
     std::vector<PlanarMotionEventEntry> motions = {
         { 0us,      {{1063, 1128}, {NAN, NAN}, {NAN, NAN}} },
         { 10800us,  {{1063, 1128}, {682, 1318}, {NAN, NAN}} }, // POINTER_DOWN
@@ -1162,7 +1155,7 @@
  * ================== Tests for least squares fitting ==============================================
  *
  * Special care must be taken when constructing tests for LeastSquaresVelocityTrackerStrategy
- * getEstimator function. In particular:
+ * getVelocity function. In particular:
  * - inside the function, time gets converted from nanoseconds to seconds
  *   before being used in the fit.
  * - any values that are older than 100 ms are being discarded.
@@ -1183,7 +1176,7 @@
  * The coefficients are (0, 0, 1).
  * In the test, we would convert these coefficients to (0*(1E3)^0, 0*(1E3)^1, 1*(1E3)^2).
  */
-TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_Constant) {
+TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategy_Constant) {
     std::vector<PlanarMotionEventEntry> motions = {
         { 0ms, {{1, 1}} }, // 0 s
         { 1ms, {{1, 1}} }, // 0.001 s
@@ -1195,13 +1188,13 @@
     // -0.002, 1
     // -0.001, 1
     // -0.ms, 1
-    computeAndCheckQuadraticEstimate(motions, std::array<float, 3>({1, 0, 0}));
+    computeAndCheckQuadraticVelocity(motions, 0);
 }
 
 /*
  * Straight line y = x :: the constant and quadratic coefficients are zero.
  */
-TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_Linear) {
+TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategy_Linear) {
     std::vector<PlanarMotionEventEntry> motions = {
         { 0ms, {{-2, -2}} },
         { 1ms, {{-1, -1}} },
@@ -1213,13 +1206,13 @@
     // -0.002, -2
     // -0.001, -1
     // -0.000,  0
-    computeAndCheckQuadraticEstimate(motions, std::array<float, 3>({0, 1E3, 0}));
+    computeAndCheckQuadraticVelocity(motions, 1E3);
 }
 
 /*
  * Parabola
  */
-TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_Parabolic) {
+TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategy_Parabolic) {
     std::vector<PlanarMotionEventEntry> motions = {
         { 0ms, {{1, 1}} },
         { 1ms, {{4, 4}} },
@@ -1231,13 +1224,13 @@
     // -0.002, 1
     // -0.001, 4
     // -0.000, 8
-    computeAndCheckQuadraticEstimate(motions, std::array<float, 3>({8, 4.5E3, 0.5E6}));
+    computeAndCheckQuadraticVelocity(motions, 4.5E3);
 }
 
 /*
  * Parabola
  */
-TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_Parabolic2) {
+TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategy_Parabolic2) {
     std::vector<PlanarMotionEventEntry> motions = {
         { 0ms, {{1, 1}} },
         { 1ms, {{4, 4}} },
@@ -1249,13 +1242,13 @@
     // -0.002, 1
     // -0.001, 4
     // -0.000, 9
-    computeAndCheckQuadraticEstimate(motions, std::array<float, 3>({9, 6E3, 1E6}));
+    computeAndCheckQuadraticVelocity(motions, 6E3);
 }
 
 /*
  * Parabola :: y = x^2 :: the constant and linear coefficients are zero.
  */
-TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategyEstimator_Parabolic3) {
+TEST_F(VelocityTrackerTest, LeastSquaresVelocityTrackerStrategy_Parabolic3) {
     std::vector<PlanarMotionEventEntry> motions = {
         { 0ms, {{4, 4}} },
         { 1ms, {{1, 1}} },
@@ -1267,7 +1260,7 @@
     // -0.002, 4
     // -0.001, 1
     // -0.000, 0
-    computeAndCheckQuadraticEstimate(motions, std::array<float, 3>({0, 0E3, 1E6}));
+    computeAndCheckQuadraticVelocity(motions, 0E3);
 }
 
 // Recorded by hand on sailfish, but only the diffs are taken to test cumulative axis velocity.
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index cd427f0..3d3a50a 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -4190,12 +4190,9 @@
                   args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_ORIENTATION));
         }
     }
-
-    if (!validateMotionEvent(args->action, args->actionButton, args->pointerCount,
-                             args->pointerProperties)) {
-        LOG(ERROR) << "Invalid event: " << args->dump();
-        return;
-    }
+    LOG_ALWAYS_FATAL_IF(!validateMotionEvent(args->action, args->actionButton, args->pointerCount,
+                                             args->pointerProperties),
+                        "Invalid event: %s", args->dump().c_str());
 
     uint32_t policyFlags = args->policyFlags;
     policyFlags |= POLICY_FLAG_TRUSTED;
diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
index f05223c..36f71bb 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
@@ -219,7 +219,7 @@
         std::lock_guard lock(mPowerHalMutex);
         HalWrapper* const halWrapper = getPowerHal();
         if (halWrapper != nullptr) {
-            halWrapper->sendActualWorkDuration(*actualDuration + kTargetSafetyMargin,
+            halWrapper->sendActualWorkDuration(*actualDuration + sTargetSafetyMargin,
                                                TimePoint::now());
         }
     }
@@ -232,12 +232,11 @@
     }
 
     const std::optional<Duration> predictedDuration = estimateWorkDuration(true);
-
     if (predictedDuration.has_value()) {
         std::lock_guard lock(mPowerHalMutex);
         HalWrapper* const halWrapper = getPowerHal();
         if (halWrapper != nullptr) {
-            halWrapper->sendActualWorkDuration(*predictedDuration + kTargetSafetyMargin,
+            halWrapper->sendActualWorkDuration(*predictedDuration + sTargetSafetyMargin,
                                                TimePoint::now());
         }
     }
@@ -812,6 +811,10 @@
 const bool AidlPowerHalWrapper::sTraceHintSessionData =
         base::GetBoolProperty(std::string("debug.sf.trace_hint_sessions"), false);
 
+const Duration PowerAdvisor::sTargetSafetyMargin = std::chrono::microseconds(
+        base::GetIntProperty<int64_t>("debug.sf.hint_margin_us",
+                                      ticks<std::micro>(PowerAdvisor::kDefaultTargetSafetyMargin)));
+
 PowerAdvisor::HalWrapper* PowerAdvisor::getPowerHal() {
     if (!mHasHal) {
         return nullptr;
diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.h b/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
index d45e7cb..c4cfdc3 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
@@ -274,7 +274,8 @@
 
     // An adjustable safety margin which pads the "actual" value sent to PowerHAL,
     // encouraging more aggressive boosting to give SurfaceFlinger a larger margin for error
-    static constexpr const Duration kTargetSafetyMargin{1ms};
+    static const Duration sTargetSafetyMargin;
+    static constexpr const Duration kDefaultTargetSafetyMargin{1ms};
 
     // How long we expect hwc to run after the present call until it waits for the fence
     static constexpr const Duration kFenceWaitStartDelayValidated{150us};
diff --git a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
index ded734e..dcc29b9 100644
--- a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
+++ b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
@@ -140,6 +140,10 @@
         janks.emplace_back("SurfaceFlinger Stuffing");
         jankType &= ~JankType::SurfaceFlingerStuffing;
     }
+    if (jankType & JankType::Dropped) {
+        janks.emplace_back("Dropped Frame");
+        jankType &= ~JankType::Dropped;
+    }
 
     // jankType should be 0 if all types of jank were checked for.
     LOG_ALWAYS_FATAL_IF(jankType != 0, "Unrecognized jank type value 0x%x", jankType);
@@ -264,6 +268,11 @@
         protoJank |= FrameTimelineEvent::JANK_SF_STUFFING;
         jankType &= ~JankType::SurfaceFlingerStuffing;
     }
+    if (jankType & JankType::Dropped) {
+        // Jank dropped does not append to other janks, it fully overrides.
+        protoJank |= FrameTimelineEvent::JANK_DROPPED;
+        jankType &= ~JankType::Dropped;
+    }
 
     // jankType should be 0 if all types of jank were checked for.
     LOG_ALWAYS_FATAL_IF(jankType != 0, "Unrecognized jank type value 0x%x", jankType);
@@ -365,8 +374,7 @@
 std::optional<int32_t> SurfaceFrame::getJankType() const {
     std::scoped_lock lock(mMutex);
     if (mPresentState == PresentState::Dropped) {
-        // Return no jank if it's a dropped frame since we cannot attribute a jank to a it.
-        return JankType::None;
+        return JankType::Dropped;
     }
     if (mActuals.presentTime == 0) {
         // Frame hasn't been presented yet.
@@ -503,7 +511,8 @@
         // We classify prediction expired as AppDeadlineMissed as the
         // TokenManager::kMaxTokens we store is large enough to account for a
         // reasonable app, so prediction expire would mean a huge scheduling delay.
-        mJankType = JankType::AppDeadlineMissed;
+        mJankType = mPresentState != PresentState::Presented ? JankType::Dropped
+                                                             : JankType::AppDeadlineMissed;
         deadlineDelta = -1;
         return;
     }
@@ -594,17 +603,17 @@
             mJankType |= displayFrameJankType;
         }
     }
+    if (mPresentState != PresentState::Presented) {
+        mJankType = JankType::Dropped;
+        // Since frame was not presented, lets drop any present value
+        mActuals.presentTime = 0;
+    }
 }
 
 void SurfaceFrame::onPresent(nsecs_t presentTime, int32_t displayFrameJankType, Fps refreshRate,
                              nsecs_t displayDeadlineDelta, nsecs_t displayPresentDelta) {
     std::scoped_lock lock(mMutex);
 
-    if (mPresentState != PresentState::Presented) {
-        // No need to update dropped buffers
-        return;
-    }
-
     mActuals.presentTime = presentTime;
     nsecs_t deadlineDelta = 0;
 
diff --git a/services/surfaceflinger/Scheduler/VsyncSchedule.h b/services/surfaceflinger/Scheduler/VsyncSchedule.h
index 763d058..0ef1e97 100644
--- a/services/surfaceflinger/Scheduler/VsyncSchedule.h
+++ b/services/surfaceflinger/Scheduler/VsyncSchedule.h
@@ -19,8 +19,8 @@
 #include <memory>
 #include <string>
 
-#include <ThreadContext.h>
 #include <android-base/thread_annotations.h>
+#include <ThreadContext.h>
 #include <ftl/enum.h>
 #include <ftl/optional.h>
 #include <scheduler/Features.h>
diff --git a/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp b/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
index d26ef3c..8911430 100644
--- a/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
+++ b/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
@@ -1198,7 +1198,7 @@
 TEST_F(FrameTimelineTest, traceSurfaceFrame_emitsValidTracePacket) {
     auto tracingSession = getTracingSessionForTest();
     // Layer specific increment
-    EXPECT_CALL(*mTimeStats, incrementJankyFrames(_));
+    EXPECT_CALL(*mTimeStats, incrementJankyFrames(_)).Times(2);
     auto presentFence1 = fenceFactory.createFenceTimeForTest(Fence::NO_FENCE);
     auto presentFence2 = fenceFactory.createFenceTimeForTest(Fence::NO_FENCE);
 
@@ -1234,8 +1234,8 @@
     auto protoDroppedSurfaceFrameActualStart =
             createProtoActualSurfaceFrameStart(traceCookie + 2, surfaceFrameToken,
                                                displayFrameToken1, sPidOne, sLayerNameOne,
-                                               FrameTimelineEvent::PRESENT_DROPPED, false, false,
-                                               FrameTimelineEvent::JANK_NONE,
+                                               FrameTimelineEvent::PRESENT_DROPPED, true, false,
+                                               FrameTimelineEvent::JANK_DROPPED,
                                                FrameTimelineEvent::PREDICTION_VALID, true);
     auto protoDroppedSurfaceFrameActualEnd = createProtoFrameEnd(traceCookie + 2);
 
@@ -1470,7 +1470,7 @@
             createProtoActualSurfaceFrameStart(traceCookie + 1, surfaceFrameToken,
                                                displayFrameToken, sPidOne, sLayerNameOne,
                                                FrameTimelineEvent::PRESENT_DROPPED, false, false,
-                                               FrameTimelineEvent::JANK_NONE,
+                                               FrameTimelineEvent::JANK_DROPPED,
                                                FrameTimelineEvent::PREDICTION_EXPIRED, true);
     auto protoActualSurfaceFrameEnd = createProtoFrameEnd(traceCookie + 1);
 
diff --git a/services/surfaceflinger/tests/unittests/PowerAdvisorTest.cpp b/services/surfaceflinger/tests/unittests/PowerAdvisorTest.cpp
index 2d66d3c..d22ce17 100644
--- a/services/surfaceflinger/tests/unittests/PowerAdvisorTest.cpp
+++ b/services/surfaceflinger/tests/unittests/PowerAdvisorTest.cpp
@@ -42,12 +42,12 @@
     void fakeBasicFrameTiming(TimePoint startTime, Duration vsyncPeriod);
     void setExpectedTiming(Duration totalFrameTargetDuration, TimePoint expectedPresentTime);
     Duration getFenceWaitDelayDuration(bool skipValidate);
+    Duration getErrorMargin();
 
 protected:
     TestableSurfaceFlinger mFlinger;
     std::unique_ptr<PowerAdvisor> mPowerAdvisor;
     NiceMock<MockAidlPowerHalWrapper>* mMockAidlWrapper;
-    Duration kErrorMargin = 1ms;
 };
 
 void PowerAdvisorTest::SetUp() FTL_FAKE_GUARD(mPowerAdvisor->mPowerHalMutex) {
@@ -77,6 +77,8 @@
     mPowerAdvisor->setCommitStart(startTime);
     mPowerAdvisor->setFrameDelay(0ns);
     mPowerAdvisor->setTargetWorkDuration(vsyncPeriod);
+    ON_CALL(*mMockAidlWrapper, getTargetWorkDuration())
+            .WillByDefault(Return(std::make_optional(vsyncPeriod)));
 }
 
 Duration PowerAdvisorTest::getFenceWaitDelayDuration(bool skipValidate) {
@@ -84,6 +86,10 @@
                          : PowerAdvisor::kFenceWaitStartDelayValidated);
 }
 
+Duration PowerAdvisorTest::getErrorMargin() {
+    return mPowerAdvisor->sTargetSafetyMargin;
+}
+
 namespace {
 
 TEST_F(PowerAdvisorTest, hintSessionUseHwcDisplay) {
@@ -109,7 +115,7 @@
     // increment the frame
     startTime += vsyncPeriod;
 
-    const Duration expectedDuration = kErrorMargin + presentDuration + postCompDuration;
+    const Duration expectedDuration = getErrorMargin() + presentDuration + postCompDuration;
     EXPECT_CALL(*mMockAidlWrapper, sendActualWorkDuration(Eq(expectedDuration), _)).Times(1);
 
     fakeBasicFrameTiming(startTime, vsyncPeriod);
@@ -145,7 +151,7 @@
     // increment the frame
     startTime += vsyncPeriod;
 
-    const Duration expectedDuration = kErrorMargin + presentDuration +
+    const Duration expectedDuration = getErrorMargin() + presentDuration +
             getFenceWaitDelayDuration(false) - hwcBlockedDuration + postCompDuration;
     EXPECT_CALL(*mMockAidlWrapper, sendActualWorkDuration(Eq(expectedDuration), _)).Times(1);
 
@@ -185,7 +191,7 @@
     // increment the frame
     startTime += vsyncPeriod;
 
-    const Duration expectedDuration = kErrorMargin + presentDuration + postCompDuration;
+    const Duration expectedDuration = getErrorMargin() + presentDuration + postCompDuration;
     EXPECT_CALL(*mMockAidlWrapper, sendActualWorkDuration(Eq(expectedDuration), _)).Times(1);
 
     fakeBasicFrameTiming(startTime, vsyncPeriod);
diff --git a/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockAidlPowerHalWrapper.h b/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockAidlPowerHalWrapper.h
index 5654691..3ed85e0 100644
--- a/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockAidlPowerHalWrapper.h
+++ b/services/surfaceflinger/tests/unittests/mock/DisplayHardware/MockAidlPowerHalWrapper.h
@@ -47,6 +47,8 @@
     MOCK_METHOD(void, sendActualWorkDuration, (Duration actualDuration, TimePoint timestamp),
                 (override));
     MOCK_METHOD(bool, shouldReconnectHAL, (), (override));
+    MOCK_METHOD(std::vector<int32_t>, getPowerHintSessionThreadIds, (), (override));
+    MOCK_METHOD(std::optional<Duration>, getTargetWorkDuration, (), (override));
 };
 
 } // namespace android::Hwc2::mock
\ No newline at end of file