diff --git a/core/java/android/view/InputDevice.java b/core/java/android/view/InputDevice.java
index 4848a7accf72c..85f435c761163 100755
--- a/core/java/android/view/InputDevice.java
+++ b/core/java/android/view/InputDevice.java
@@ -167,6 +167,19 @@ public final class InputDevice implements Parcelable {
 
     /**
      * The input source is a stylus pointing device.
+     * <p>
+     * Note that this bit merely indicates that an input device is capable of obtaining
+     * input from a stylus.  To determine whether a given touch event was produced
+     * by a stylus, examine the tool type returned by {@link MotionEvent#getToolType(int)}
+     * for each individual pointer.
+     * </p><p>
+     * A single touch event may multiple pointers with different tool types,
+     * such as an event that has one pointer with tool type
+     * {@link MotionEvent#TOOL_TYPE_FINGER} and another pointer with tool type
+     * {@link MotionEvent#TOOL_TYPE_STYLUS}.  So it is important to examine
+     * the tool type of each pointer, regardless of the source reported
+     * by {@link MotionEvent#getSource()}.
+     * </p>
      *
      * @see #SOURCE_CLASS_POINTER
      */
diff --git a/services/input/InputReader.cpp b/services/input/InputReader.cpp
index 4cc3d44623f30..3a48b1607130a 100644
--- a/services/input/InputReader.cpp
+++ b/services/input/InputReader.cpp
@@ -1292,12 +1292,17 @@ void CursorScrollAccumulator::finishSync() {
 // --- TouchButtonAccumulator ---
 
 TouchButtonAccumulator::TouchButtonAccumulator() :
-        mHaveBtnTouch(false) {
+        mHaveBtnTouch(false), mHaveStylus(false) {
     clearButtons();
 }
 
 void TouchButtonAccumulator::configure(InputDevice* device) {
     mHaveBtnTouch = device->hasKey(BTN_TOUCH);
+    mHaveStylus = device->hasKey(BTN_TOOL_PEN)
+            || device->hasKey(BTN_TOOL_RUBBER)
+            || device->hasKey(BTN_TOOL_BRUSH)
+            || device->hasKey(BTN_TOOL_PENCIL)
+            || device->hasKey(BTN_TOOL_AIRBRUSH);
 }
 
 void TouchButtonAccumulator::reset(InputDevice* device) {
@@ -1421,6 +1426,10 @@ bool TouchButtonAccumulator::isHovering() const {
     return mHaveBtnTouch && !mBtnTouch;
 }
 
+bool TouchButtonAccumulator::hasStylus() const {
+    return mHaveStylus;
+}
+
 
 // --- RawPointerAxes ---
 
@@ -1572,16 +1581,19 @@ void SingleTouchMotionAccumulator::process(const RawEvent* rawEvent) {
 // --- MultiTouchMotionAccumulator ---
 
 MultiTouchMotionAccumulator::MultiTouchMotionAccumulator() :
-        mCurrentSlot(-1), mSlots(NULL), mSlotCount(0), mUsingSlotsProtocol(false) {
+        mCurrentSlot(-1), mSlots(NULL), mSlotCount(0), mUsingSlotsProtocol(false),
+        mHaveStylus(false) {
 }
 
 MultiTouchMotionAccumulator::~MultiTouchMotionAccumulator() {
     delete[] mSlots;
 }
 
-void MultiTouchMotionAccumulator::configure(size_t slotCount, bool usingSlotsProtocol) {
+void MultiTouchMotionAccumulator::configure(InputDevice* device,
+        size_t slotCount, bool usingSlotsProtocol) {
     mSlotCount = slotCount;
     mUsingSlotsProtocol = usingSlotsProtocol;
+    mHaveStylus = device->hasAbsoluteAxis(ABS_MT_TOOL_TYPE);
 
     delete[] mSlots;
     mSlots = new Slot[slotCount];
@@ -1713,6 +1725,10 @@ void MultiTouchMotionAccumulator::finishSync() {
     }
 }
 
+bool MultiTouchMotionAccumulator::hasStylus() const {
+    return mHaveStylus;
+}
+
 
 // --- MultiTouchMotionAccumulator::Slot ---
 
@@ -2872,10 +2888,16 @@ void TouchInputMapper::configureSurface(nsecs_t when, bool* outResetNeeded) {
             && mConfig.pointerGesturesEnabled) {
         mSource = AINPUT_SOURCE_MOUSE;
         mDeviceMode = DEVICE_MODE_POINTER;
+        if (hasStylus()) {
+            mSource |= AINPUT_SOURCE_STYLUS;
+        }
     } else if (mParameters.deviceType == Parameters::DEVICE_TYPE_TOUCH_SCREEN
             && mParameters.associatedDisplayId >= 0) {
         mSource = AINPUT_SOURCE_TOUCHSCREEN;
         mDeviceMode = DEVICE_MODE_DIRECT;
+        if (hasStylus()) {
+            mSource |= AINPUT_SOURCE_STYLUS;
+        }
     } else {
         mSource = AINPUT_SOURCE_TOUCHPAD;
         mDeviceMode = DEVICE_MODE_UNSCALED;
@@ -5786,6 +5808,10 @@ void SingleTouchInputMapper::configureRawPointerAxes() {
     getAbsoluteAxisInfo(ABS_TILT_Y, &mRawPointerAxes.tiltY);
 }
 
+bool SingleTouchInputMapper::hasStylus() const {
+    return mTouchButtonAccumulator.hasStylus();
+}
+
 
 // --- MultiTouchInputMapper ---
 
@@ -5920,12 +5946,19 @@ void MultiTouchInputMapper::configureRawPointerAxes() {
                     getDeviceName().string(), slotCount, MAX_SLOTS);
             slotCount = MAX_SLOTS;
         }
-        mMultiTouchMotionAccumulator.configure(slotCount, true /*usingSlotsProtocol*/);
+        mMultiTouchMotionAccumulator.configure(getDevice(),
+                slotCount, true /*usingSlotsProtocol*/);
     } else {
-        mMultiTouchMotionAccumulator.configure(MAX_POINTERS, false /*usingSlotsProtocol*/);
+        mMultiTouchMotionAccumulator.configure(getDevice(),
+                MAX_POINTERS, false /*usingSlotsProtocol*/);
     }
 }
 
+bool MultiTouchInputMapper::hasStylus() const {
+    return mMultiTouchMotionAccumulator.hasStylus()
+            || mTouchButtonAccumulator.hasStylus();
+}
+
 
 // --- JoystickInputMapper ---
 
diff --git a/services/input/InputReader.h b/services/input/InputReader.h
index e5897e7051eec..acdec85a6ae5c 100644
--- a/services/input/InputReader.h
+++ b/services/input/InputReader.h
@@ -507,6 +507,12 @@ public:
         return getEventHub()->hasScanCode(mId, code);
     }
 
+    bool hasAbsoluteAxis(int32_t code) {
+        RawAbsoluteAxisInfo info;
+        getEventHub()->getAbsoluteAxisInfo(mId, code, &info);
+        return info.valid;
+    }
+
     bool isKeyPressed(int32_t code) {
         return getEventHub()->getScanCodeState(mId, code) == AKEY_STATE_DOWN;
     }
@@ -627,9 +633,11 @@ public:
     int32_t getToolType() const;
     bool isToolActive() const;
     bool isHovering() const;
+    bool hasStylus() const;
 
 private:
     bool mHaveBtnTouch;
+    bool mHaveStylus;
 
     bool mBtnTouch;
     bool mBtnStylus;
@@ -817,10 +825,11 @@ public:
     MultiTouchMotionAccumulator();
     ~MultiTouchMotionAccumulator();
 
-    void configure(size_t slotCount, bool usingSlotsProtocol);
+    void configure(InputDevice* device, size_t slotCount, bool usingSlotsProtocol);
     void reset(InputDevice* device);
     void process(const RawEvent* rawEvent);
     void finishSync();
+    bool hasStylus() const;
 
     inline size_t getSlotCount() const { return mSlotCount; }
     inline const Slot* getSlot(size_t index) const { return &mSlots[index]; }
@@ -830,6 +839,7 @@ private:
     Slot* mSlots;
     size_t mSlotCount;
     bool mUsingSlotsProtocol;
+    bool mHaveStylus;
 
     void clearSlots(int32_t initialSlot);
 };
@@ -1257,6 +1267,7 @@ protected:
     virtual void parseCalibration();
     virtual void resolveCalibration();
     virtual void dumpCalibration(String8& dump);
+    virtual bool hasStylus() const = 0;
 
     virtual void syncTouch(nsecs_t when, bool* outHavePointerIds) = 0;
 
@@ -1605,6 +1616,7 @@ public:
 protected:
     virtual void syncTouch(nsecs_t when, bool* outHavePointerIds);
     virtual void configureRawPointerAxes();
+    virtual bool hasStylus() const;
 
 private:
     SingleTouchMotionAccumulator mSingleTouchMotionAccumulator;
@@ -1622,6 +1634,7 @@ public:
 protected:
     virtual void syncTouch(nsecs_t when, bool* outHavePointerIds);
     virtual void configureRawPointerAxes();
+    virtual bool hasStylus() const;
 
 private:
     MultiTouchMotionAccumulator mMultiTouchMotionAccumulator;