diff --git a/services/inputflinger/reader/InputDevice.cpp b/services/inputflinger/reader/InputDevice.cpp
index b86906b..ec8a443 100644
--- a/services/inputflinger/reader/InputDevice.cpp
+++ b/services/inputflinger/reader/InputDevice.cpp
@@ -203,7 +203,7 @@
 
     using Change = InputReaderConfiguration::Change;
 
-    if (!isIgnored()) {
+    if (!changes.any() || !isIgnored()) {
         // Full configuration should happen the first time configure is called
         // and when the device type is changed. Changing a device type can
         // affect various other parameters so should result in a
@@ -503,9 +503,9 @@
         classes.test(InputDeviceClass::TOUCH_MT) && !isSonyDualShock4Touchpad) {
         mappers.push_back(std::make_unique<TouchpadInputMapper>(contextPtr, readerConfig));
     } else if (classes.test(InputDeviceClass::TOUCH_MT)) {
-        mappers.push_back(std::make_unique<MultiTouchInputMapper>(contextPtr, readerConfig));
+        mappers.push_back(createInputMapper<MultiTouchInputMapper>(contextPtr, readerConfig));
     } else if (classes.test(InputDeviceClass::TOUCH)) {
-        mappers.push_back(std::make_unique<SingleTouchInputMapper>(contextPtr, readerConfig));
+        mappers.push_back(createInputMapper<SingleTouchInputMapper>(contextPtr, readerConfig));
     }
 
     // Joystick-like devices.
diff --git a/services/inputflinger/reader/include/InputDevice.h b/services/inputflinger/reader/include/InputDevice.h
index 6303546..0b8a608 100644
--- a/services/inputflinger/reader/include/InputDevice.h
+++ b/services/inputflinger/reader/include/InputDevice.h
@@ -149,6 +149,16 @@
         return *mapper;
     }
 
+    template <class T, typename... Args>
+    T& constructAndAddMapper(int32_t eventHubId, Args... args) {
+        // create mapper
+        auto& devicePair = mDevices[eventHubId];
+        auto& deviceContext = devicePair.first;
+        auto& mappers = devicePair.second;
+        mappers.push_back(createInputMapper<T>(*deviceContext, args...));
+        return static_cast<T&>(*mappers.back());
+    }
+
     // construct and add a controller to the input device
     template <class T>
     T& addController(int32_t eventHubId) {
diff --git a/services/inputflinger/reader/mapper/InputMapper.h b/services/inputflinger/reader/mapper/InputMapper.h
index f017317..06de4c2 100644
--- a/services/inputflinger/reader/mapper/InputMapper.h
+++ b/services/inputflinger/reader/mapper/InputMapper.h
@@ -25,6 +25,20 @@
 #include "VibrationElement.h"
 
 namespace android {
+/**
+ * This is the factory method that must be used to create any InputMapper
+ */
+template <class T, class... Args>
+std::unique_ptr<T> createInputMapper(InputDeviceContext& deviceContext,
+                                     const InputReaderConfiguration& readerConfig, Args... args) {
+    // Using `new` to access non-public constructors.
+    std::unique_ptr<T> mapper(new T(deviceContext, readerConfig, args...));
+    // We need to reset and configure the mapper to ensure it is ready to process event
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+    std::list<NotifyArgs> unused = mapper->reset(now);
+    unused += mapper->reconfigure(now, readerConfig, /*changes=*/{});
+    return mapper;
+}
 
 /* An input mapper transforms raw input events into cooked event data.
  * A single input device can have multiple associated input mappers in order to interpret
@@ -39,8 +53,15 @@
  */
 class InputMapper {
 public:
-    explicit InputMapper(InputDeviceContext& deviceContext,
-                         const InputReaderConfiguration& readerConfig);
+    /**
+     * Subclasses must either provide a public constructor
+     * or must be-friend the factory method.
+     */
+    template <class T, class... Args>
+    friend std::unique_ptr<T> createInputMapper(InputDeviceContext& deviceContext,
+                                                const InputReaderConfiguration& readerConfig,
+                                                Args... args);
+
     virtual ~InputMapper();
 
     inline int32_t getDeviceId() { return mDeviceContext.getId(); }
@@ -102,6 +123,9 @@
 protected:
     InputDeviceContext& mDeviceContext;
 
+    explicit InputMapper(InputDeviceContext& deviceContext,
+                         const InputReaderConfiguration& readerConfig);
+
     status_t getAbsoluteAxisInfo(int32_t axis, RawAbsoluteAxisInfo* axisInfo);
     void bumpGeneration();
 
diff --git a/services/inputflinger/reader/mapper/MultiTouchInputMapper.h b/services/inputflinger/reader/mapper/MultiTouchInputMapper.h
index a617420..1d788df 100644
--- a/services/inputflinger/reader/mapper/MultiTouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/MultiTouchInputMapper.h
@@ -23,8 +23,11 @@
 
 class MultiTouchInputMapper : public TouchInputMapper {
 public:
-    explicit MultiTouchInputMapper(InputDeviceContext& deviceContext,
-                                   const InputReaderConfiguration& readerConfig);
+    template <class T, class... Args>
+    friend std::unique_ptr<T> createInputMapper(InputDeviceContext& deviceContext,
+                                                const InputReaderConfiguration& readerConfig,
+                                                Args... args);
+
     ~MultiTouchInputMapper() override;
 
     [[nodiscard]] std::list<NotifyArgs> reset(nsecs_t when) override;
@@ -36,6 +39,8 @@
     bool hasStylus() const override;
 
 private:
+    explicit MultiTouchInputMapper(InputDeviceContext& deviceContext,
+                                   const InputReaderConfiguration& readerConfig);
     // simulate_stylus_with_touch is a debug mode that converts all finger pointers reported by this
     // mapper's touchscreen into stylus pointers, and adds SOURCE_STYLUS to the input device.
     // It is used to simulate stylus events for debugging and testing on a device that does not
diff --git a/services/inputflinger/reader/mapper/SingleTouchInputMapper.h b/services/inputflinger/reader/mapper/SingleTouchInputMapper.h
index 9341007..7726bfb 100644
--- a/services/inputflinger/reader/mapper/SingleTouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/SingleTouchInputMapper.h
@@ -23,8 +23,11 @@
 
 class SingleTouchInputMapper : public TouchInputMapper {
 public:
-    explicit SingleTouchInputMapper(InputDeviceContext& deviceContext,
-                                    const InputReaderConfiguration& readerConfig);
+    template <class T, class... Args>
+    friend std::unique_ptr<T> createInputMapper(InputDeviceContext& deviceContext,
+                                                const InputReaderConfiguration& readerConfig,
+                                                Args... args);
+
     ~SingleTouchInputMapper() override;
 
     [[nodiscard]] std::list<NotifyArgs> reset(nsecs_t when) override;
@@ -37,6 +40,8 @@
 
 private:
     SingleTouchMotionAccumulator mSingleTouchMotionAccumulator;
+    explicit SingleTouchInputMapper(InputDeviceContext& deviceContext,
+                                    const InputReaderConfiguration& readerConfig);
 };
 
 } // namespace android
diff --git a/services/inputflinger/reader/mapper/TouchInputMapper.cpp b/services/inputflinger/reader/mapper/TouchInputMapper.cpp
index c72a263..f4d50b8 100644
--- a/services/inputflinger/reader/mapper/TouchInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/TouchInputMapper.cpp
@@ -125,8 +125,7 @@
                                    const InputReaderConfiguration& readerConfig)
       : InputMapper(deviceContext, readerConfig),
         mTouchButtonAccumulator(deviceContext),
-        mConfig(readerConfig),
-        mParameters(computeParameters(deviceContext)) {}
+        mConfig(readerConfig) {}
 
 TouchInputMapper::~TouchInputMapper() {}
 
diff --git a/services/inputflinger/reader/mapper/TouchInputMapper.h b/services/inputflinger/reader/mapper/TouchInputMapper.h
index 7141924..d8b59ca 100644
--- a/services/inputflinger/reader/mapper/TouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/TouchInputMapper.h
@@ -146,8 +146,6 @@
 
 class TouchInputMapper : public InputMapper {
 public:
-    explicit TouchInputMapper(InputDeviceContext& deviceContext,
-                              const InputReaderConfiguration& readerConfig);
     ~TouchInputMapper() override;
 
     uint32_t getSources() const override;
@@ -358,25 +356,28 @@
     nsecs_t mExternalStylusFusionTimeout;
     bool mExternalStylusDataPending;
     // A subset of the buttons in mCurrentRawState that came from an external stylus.
-    int32_t mExternalStylusButtonsApplied;
+    int32_t mExternalStylusButtonsApplied{0};
 
     // True if we sent a HOVER_ENTER event.
-    bool mSentHoverEnter;
+    bool mSentHoverEnter{false};
 
     // Have we assigned pointer IDs for this stream
-    bool mHavePointerIds;
+    bool mHavePointerIds{false};
 
     // Is the current stream of direct touch events aborted
-    bool mCurrentMotionAborted;
+    bool mCurrentMotionAborted{false};
 
     // The time the primary pointer last went down.
-    nsecs_t mDownTime;
+    nsecs_t mDownTime{0};
 
     // The pointer controller, or null if the device is not a pointer.
     std::shared_ptr<PointerControllerInterface> mPointerController;
 
     std::vector<VirtualKey> mVirtualKeys;
 
+    explicit TouchInputMapper(InputDeviceContext& deviceContext,
+                              const InputReaderConfiguration& readerConfig);
+
     virtual void dumpParameters(std::string& dump);
     virtual void configureRawPointerAxes();
     virtual void dumpRawPointerAxes(std::string& dump);
@@ -513,7 +514,7 @@
         STYLUS,
         MOUSE,
     };
-    PointerUsage mPointerUsage;
+    PointerUsage mPointerUsage{PointerUsage::NONE};
 
     struct PointerGesture {
         enum class Mode {