Add sequence number to events in inputflinger

This adds a sequece number field to NotifyArgs and EventEntry in order to
uniquely track individual events.

The sequence number for the events is added in InputReader, where the next
sequence number is an increment of the previous event's sequence number.
Synthesized events have a sequence number of 0.

Bug: 119312685
Test: inputflinger_tests
Change-Id: I1690979a5aa019e99ab89f5f7279a1b42068e658

7 files changed, 166 insertions, 87 deletions

diff --git a/services/inputflinger/InputDispatcher.cpp b/services/inputflinger/InputDispatcher.cpp
index ac17dcaa7f..6879a73251 100644
--- a/services/inputflinger/InputDispatcher.cpp
+++ b/services/inputflinger/InputDispatcher.cpp
@@ -97,6 +97,9 @@ constexpr std::chrono::milliseconds SLOW_INTERCEPTION_THRESHOLD = 50ms;
 // Number of recent events to keep for debugging purposes.
 constexpr size_t RECENT_QUEUE_MAX_SIZE = 10;
 
+// Sequence number for synthesized or injected events.
+constexpr uint32_t SYNTHESIZED_EVENT_SEQUENCE_NUM = 0;
+
 
 static inline nsecs_t now() {
     return systemTime(SYSTEM_TIME_MONOTONIC);
@@ -710,7 +713,7 @@ InputDispatcher::KeyEntry* InputDispatcher::synthesizeKeyRepeatLocked(nsecs_t cu
         entry->policyFlags = policyFlags;
         entry->repeatCount += 1;
     } else {
-        KeyEntry* newEntry = new KeyEntry(currentTime,
+        KeyEntry* newEntry = new KeyEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, currentTime,
                 entry->deviceId, entry->source, entry->displayId, policyFlags,
                 entry->action, entry->flags, entry->keyCode, entry->scanCode,
                 entry->metaState, entry->repeatCount + 1, entry->downTime);
@@ -2474,6 +2477,7 @@ InputDispatcher::splitMotionEvent(const MotionEntry* originalMotionEntry, BitSet
     }
 
     MotionEntry* splitMotionEntry = new MotionEntry(
+            originalMotionEntry->sequenceNum,
             originalMotionEntry->eventTime,
             originalMotionEntry->deviceId,
             originalMotionEntry->source,
@@ -2507,7 +2511,8 @@ void InputDispatcher::notifyConfigurationChanged(const NotifyConfigurationChange
     { // acquire lock
         AutoMutex _l(mLock);
 
-        ConfigurationChangedEntry* newEntry = new ConfigurationChangedEntry(args->eventTime);
+        ConfigurationChangedEntry* newEntry =
+                new ConfigurationChangedEntry(args->sequenceNum, args->eventTime);
         needWake = enqueueInboundEventLocked(newEntry);
     } // release lock
 
@@ -2612,7 +2617,7 @@ void InputDispatcher::notifyKey(const NotifyKeyArgs* args) {
             mLock.lock();
         }
 
-        KeyEntry* newEntry = new KeyEntry(args->eventTime,
+        KeyEntry* newEntry = new KeyEntry(args->sequenceNum, args->eventTime,
                 args->deviceId, args->source, args->displayId, policyFlags,
                 args->action, flags, keyCode, args->scanCode,
                 metaState, repeatCount, args->downTime);
@@ -2696,7 +2701,7 @@ void InputDispatcher::notifyMotion(const NotifyMotionArgs* args) {
         }
 
         // Just enqueue a new motion event.
-        MotionEntry* newEntry = new MotionEntry(args->eventTime,
+        MotionEntry* newEntry = new MotionEntry(args->sequenceNum, args->eventTime,
                 args->deviceId, args->source, args->displayId, policyFlags,
                 args->action, args->actionButton, args->flags,
                 args->metaState, args->buttonState,
@@ -2740,7 +2745,8 @@ void InputDispatcher::notifyDeviceReset(const NotifyDeviceResetArgs* args) {
     { // acquire lock
         AutoMutex _l(mLock);
 
-        DeviceResetEntry* newEntry = new DeviceResetEntry(args->eventTime, args->deviceId);
+        DeviceResetEntry* newEntry =
+                new DeviceResetEntry(args->sequenceNum, args->eventTime, args->deviceId);
         needWake = enqueueInboundEventLocked(newEntry);
     } // release lock
 
@@ -2799,7 +2805,7 @@ int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
         }
 
         mLock.lock();
-        firstInjectedEntry = new KeyEntry(keyEvent.getEventTime(),
+        firstInjectedEntry = new KeyEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, keyEvent.getEventTime(),
                 keyEvent.getDeviceId(), keyEvent.getSource(), keyEvent.getDisplayId(),
                 policyFlags, action, flags,
                 keyEvent.getKeyCode(), keyEvent.getScanCode(), keyEvent.getMetaState(),
@@ -2831,7 +2837,7 @@ int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
         mLock.lock();
         const nsecs_t* sampleEventTimes = motionEvent->getSampleEventTimes();
         const PointerCoords* samplePointerCoords = motionEvent->getSamplePointerCoords();
-        firstInjectedEntry = new MotionEntry(*sampleEventTimes,
+        firstInjectedEntry = new MotionEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, *sampleEventTimes,
                 motionEvent->getDeviceId(), motionEvent->getSource(), motionEvent->getDisplayId(),
                 policyFlags,
                 action, actionButton, motionEvent->getFlags(),
@@ -2845,7 +2851,8 @@ int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
         for (size_t i = motionEvent->getHistorySize(); i > 0; i--) {
             sampleEventTimes += 1;
             samplePointerCoords += pointerCount;
-            MotionEntry* nextInjectedEntry = new MotionEntry(*sampleEventTimes,
+            MotionEntry* nextInjectedEntry = new MotionEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM,
+                    *sampleEventTimes,
                     motionEvent->getDeviceId(), motionEvent->getSource(),
                     motionEvent->getDisplayId(), policyFlags,
                     action, actionButton, motionEvent->getFlags(),
@@ -4279,9 +4286,10 @@ void InputDispatcher::InjectionState::release() {
 
 // --- InputDispatcher::EventEntry ---
 
-InputDispatcher::EventEntry::EventEntry(int32_t type, nsecs_t eventTime, uint32_t policyFlags) :
-        refCount(1), type(type), eventTime(eventTime), policyFlags(policyFlags),
-        injectionState(nullptr), dispatchInProgress(false) {
+InputDispatcher::EventEntry::EventEntry(uint32_t sequenceNum, int32_t type,
+        nsecs_t eventTime, uint32_t policyFlags) :
+        sequenceNum(sequenceNum), refCount(1), type(type), eventTime(eventTime),
+        policyFlags(policyFlags), injectionState(nullptr), dispatchInProgress(false) {
 }
 
 InputDispatcher::EventEntry::~EventEntry() {
@@ -4307,8 +4315,9 @@ void InputDispatcher::EventEntry::releaseInjectionState() {
 
 // --- InputDispatcher::ConfigurationChangedEntry ---
 
-InputDispatcher::ConfigurationChangedEntry::ConfigurationChangedEntry(nsecs_t eventTime) :
-        EventEntry(TYPE_CONFIGURATION_CHANGED, eventTime, 0) {
+InputDispatcher::ConfigurationChangedEntry::ConfigurationChangedEntry(
+        uint32_t sequenceNum, nsecs_t eventTime) :
+        EventEntry(sequenceNum, TYPE_CONFIGURATION_CHANGED, eventTime, 0) {
 }
 
 InputDispatcher::ConfigurationChangedEntry::~ConfigurationChangedEntry() {
@@ -4321,8 +4330,9 @@ void InputDispatcher::ConfigurationChangedEntry::appendDescription(std::string&
 
 // --- InputDispatcher::DeviceResetEntry ---
 
-InputDispatcher::DeviceResetEntry::DeviceResetEntry(nsecs_t eventTime, int32_t deviceId) :
-        EventEntry(TYPE_DEVICE_RESET, eventTime, 0),
+InputDispatcher::DeviceResetEntry::DeviceResetEntry(
+        uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId) :
+        EventEntry(sequenceNum, TYPE_DEVICE_RESET, eventTime, 0),
         deviceId(deviceId) {
 }
 
@@ -4337,11 +4347,11 @@ void InputDispatcher::DeviceResetEntry::appendDescription(std::string& msg) cons
 
 // --- InputDispatcher::KeyEntry ---
 
-InputDispatcher::KeyEntry::KeyEntry(nsecs_t eventTime,
+InputDispatcher::KeyEntry::KeyEntry(uint32_t sequenceNum, nsecs_t eventTime,
         int32_t deviceId, uint32_t source, int32_t displayId, uint32_t policyFlags, int32_t action,
         int32_t flags, int32_t keyCode, int32_t scanCode, int32_t metaState,
         int32_t repeatCount, nsecs_t downTime) :
-        EventEntry(TYPE_KEY, eventTime, policyFlags),
+        EventEntry(sequenceNum, TYPE_KEY, eventTime, policyFlags),
         deviceId(deviceId), source(source), displayId(displayId), action(action), flags(flags),
         keyCode(keyCode), scanCode(scanCode), metaState(metaState),
         repeatCount(repeatCount), downTime(downTime),
@@ -4372,7 +4382,7 @@ void InputDispatcher::KeyEntry::recycle() {
 
 // --- InputDispatcher::MotionEntry ---
 
-InputDispatcher::MotionEntry::MotionEntry(nsecs_t eventTime, int32_t deviceId,
+InputDispatcher::MotionEntry::MotionEntry(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId,
         uint32_t source, int32_t displayId, uint32_t policyFlags, int32_t action,
         int32_t actionButton,
         int32_t flags, int32_t metaState, int32_t buttonState, int32_t edgeFlags,
@@ -4380,7 +4390,7 @@ InputDispatcher::MotionEntry::MotionEntry(nsecs_t eventTime, int32_t deviceId,
         uint32_t pointerCount,
         const PointerProperties* pointerProperties, const PointerCoords* pointerCoords,
         float xOffset, float yOffset) :
-        EventEntry(TYPE_MOTION, eventTime, policyFlags),
+        EventEntry(sequenceNum, TYPE_MOTION, eventTime, policyFlags),
         eventTime(eventTime),
         deviceId(deviceId), source(source), displayId(displayId), action(action),
         actionButton(actionButton), flags(flags), metaState(metaState), buttonState(buttonState),
@@ -4694,7 +4704,7 @@ void InputDispatcher::InputState::synthesizeCancelationEvents(nsecs_t currentTim
     for (size_t i = 0; i < mKeyMementos.size(); i++) {
         const KeyMemento& memento = mKeyMementos.itemAt(i);
         if (shouldCancelKey(memento, options)) {
-            outEvents.push(new KeyEntry(currentTime,
+            outEvents.push(new KeyEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, currentTime,
                     memento.deviceId, memento.source, memento.displayId, memento.policyFlags,
                     AKEY_EVENT_ACTION_UP, memento.flags | AKEY_EVENT_FLAG_CANCELED,
                     memento.keyCode, memento.scanCode, memento.metaState, 0, memento.downTime));
@@ -4704,7 +4714,7 @@ void InputDispatcher::InputState::synthesizeCancelationEvents(nsecs_t currentTim
     for (size_t i = 0; i < mMotionMementos.size(); i++) {
         const MotionMemento& memento = mMotionMementos.itemAt(i);
         if (shouldCancelMotion(memento, options)) {
-            outEvents.push(new MotionEntry(currentTime,
+            outEvents.push(new MotionEntry(SYNTHESIZED_EVENT_SEQUENCE_NUM, currentTime,
                     memento.deviceId, memento.source, memento.displayId, memento.policyFlags,
                     memento.hovering
                             ? AMOTION_EVENT_ACTION_HOVER_EXIT
diff --git a/services/inputflinger/InputDispatcher.h b/services/inputflinger/InputDispatcher.h
index 73bcc25848..05b5dadc66 100644
--- a/services/inputflinger/InputDispatcher.h
+++ b/services/inputflinger/InputDispatcher.h
@@ -454,6 +454,7 @@ private:
             TYPE_MOTION
         };
 
+        uint32_t sequenceNum;
         mutable int32_t refCount;
         int32_t type;
         nsecs_t eventTime;
@@ -469,13 +470,13 @@ private:
         virtual void appendDescription(std::string& msg) const = 0;
 
     protected:
-        EventEntry(int32_t type, nsecs_t eventTime, uint32_t policyFlags);
+        EventEntry(uint32_t sequenceNum, int32_t type, nsecs_t eventTime, uint32_t policyFlags);
         virtual ~EventEntry();
         void releaseInjectionState();
     };
 
     struct ConfigurationChangedEntry : EventEntry {
-        explicit ConfigurationChangedEntry(nsecs_t eventTime);
+        explicit ConfigurationChangedEntry(uint32_t sequenceNum, nsecs_t eventTime);
         virtual void appendDescription(std::string& msg) const;
 
     protected:
@@ -485,7 +486,7 @@ private:
     struct DeviceResetEntry : EventEntry {
         int32_t deviceId;
 
-        DeviceResetEntry(nsecs_t eventTime, int32_t deviceId);
+        DeviceResetEntry(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId);
         virtual void appendDescription(std::string& msg) const;
 
     protected:
@@ -515,7 +516,7 @@ private:
         InterceptKeyResult interceptKeyResult; // set based on the interception result
         nsecs_t interceptKeyWakeupTime; // used with INTERCEPT_KEY_RESULT_TRY_AGAIN_LATER
 
-        KeyEntry(nsecs_t eventTime,
+        KeyEntry(uint32_t sequenceNum, nsecs_t eventTime,
                 int32_t deviceId, uint32_t source, int32_t displayId, uint32_t policyFlags,
                 int32_t action, int32_t flags, int32_t keyCode, int32_t scanCode, int32_t metaState,
                 int32_t repeatCount, nsecs_t downTime);
@@ -544,7 +545,7 @@ private:
         PointerProperties pointerProperties[MAX_POINTERS];
         PointerCoords pointerCoords[MAX_POINTERS];
 
-        MotionEntry(nsecs_t eventTime,
+        MotionEntry(uint32_t sequenceNum, nsecs_t eventTime,
                 int32_t deviceId, uint32_t source, int32_t displayId, uint32_t policyFlags,
                 int32_t action, int32_t actionButton, int32_t flags,
                 int32_t metaState, int32_t buttonState, int32_t edgeFlags,
diff --git a/services/inputflinger/InputListener.cpp b/services/inputflinger/InputListener.cpp
index 25a39a8274..23cceb4713 100644
--- a/services/inputflinger/InputListener.cpp
+++ b/services/inputflinger/InputListener.cpp
@@ -26,13 +26,14 @@ namespace android {
 
 // --- NotifyConfigurationChangedArgs ---
 
-NotifyConfigurationChangedArgs::NotifyConfigurationChangedArgs(nsecs_t eventTime) :
-        eventTime(eventTime) {
+NotifyConfigurationChangedArgs::NotifyConfigurationChangedArgs(
+        uint32_t sequenceNum, nsecs_t eventTime) :
+        NotifyArgs(sequenceNum), eventTime(eventTime) {
 }
 
 NotifyConfigurationChangedArgs::NotifyConfigurationChangedArgs(
         const NotifyConfigurationChangedArgs& other) :
-        eventTime(other.eventTime) {
+        NotifyArgs(other.sequenceNum), eventTime(other.eventTime) {
 }
 
 void NotifyConfigurationChangedArgs::notify(const sp<InputListenerInterface>& listener) const {
@@ -42,19 +43,19 @@ void NotifyConfigurationChangedArgs::notify(const sp<InputListenerInterface>& li
 
 // --- NotifyKeyArgs ---
 
-NotifyKeyArgs::NotifyKeyArgs(nsecs_t eventTime, int32_t deviceId, uint32_t source,
-        int32_t displayId, uint32_t policyFlags,
+NotifyKeyArgs::NotifyKeyArgs(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId,
+        uint32_t source, int32_t displayId, uint32_t policyFlags,
         int32_t action, int32_t flags, int32_t keyCode, int32_t scanCode,
         int32_t metaState, nsecs_t downTime) :
-        eventTime(eventTime), deviceId(deviceId), source(source), displayId(displayId),
-        policyFlags(policyFlags),
+        NotifyArgs(sequenceNum), eventTime(eventTime), deviceId(deviceId), source(source),
+        displayId(displayId), policyFlags(policyFlags),
         action(action), flags(flags), keyCode(keyCode), scanCode(scanCode),
         metaState(metaState), downTime(downTime) {
 }
 
 NotifyKeyArgs::NotifyKeyArgs(const NotifyKeyArgs& other) :
-        eventTime(other.eventTime), deviceId(other.deviceId), source(other.source),
-        displayId(other.displayId), policyFlags(other.policyFlags),
+        NotifyArgs(other.sequenceNum), eventTime(other.eventTime), deviceId(other.deviceId),
+        source(other.source), displayId(other.displayId), policyFlags(other.policyFlags),
         action(other.action), flags(other.flags),
         keyCode(other.keyCode), scanCode(other.scanCode),
         metaState(other.metaState), downTime(other.downTime) {
@@ -67,15 +68,15 @@ void NotifyKeyArgs::notify(const sp<InputListenerInterface>& listener) const {
 
 // --- NotifyMotionArgs ---
 
-NotifyMotionArgs::NotifyMotionArgs(nsecs_t eventTime, int32_t deviceId, uint32_t source,
-        int32_t displayId, uint32_t policyFlags,
+NotifyMotionArgs::NotifyMotionArgs(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId,
+        uint32_t source, int32_t displayId, uint32_t policyFlags,
         int32_t action, int32_t actionButton, int32_t flags, int32_t metaState,
         int32_t buttonState, int32_t edgeFlags, uint32_t deviceTimestamp,
         uint32_t pointerCount,
         const PointerProperties* pointerProperties, const PointerCoords* pointerCoords,
         float xPrecision, float yPrecision, nsecs_t downTime) :
-        eventTime(eventTime), deviceId(deviceId), source(source), displayId(displayId),
-        policyFlags(policyFlags),
+        NotifyArgs(sequenceNum), eventTime(eventTime), deviceId(deviceId), source(source),
+        displayId(displayId), policyFlags(policyFlags),
         action(action), actionButton(actionButton),
         flags(flags), metaState(metaState), buttonState(buttonState),
         edgeFlags(edgeFlags), deviceTimestamp(deviceTimestamp),
@@ -88,8 +89,8 @@ NotifyMotionArgs::NotifyMotionArgs(nsecs_t eventTime, int32_t deviceId, uint32_t
 }
 
 NotifyMotionArgs::NotifyMotionArgs(const NotifyMotionArgs& other) :
-        eventTime(other.eventTime), deviceId(other.deviceId), source(other.source),
-        displayId(other.displayId), policyFlags(other.policyFlags),
+        NotifyArgs(other.sequenceNum), eventTime(other.eventTime), deviceId(other.deviceId),
+        source(other.source), displayId(other.displayId), policyFlags(other.policyFlags),
         action(other.action), actionButton(other.actionButton), flags(other.flags),
         metaState(other.metaState), buttonState(other.buttonState),
         edgeFlags(other.edgeFlags),
@@ -108,14 +109,14 @@ void NotifyMotionArgs::notify(const sp<InputListenerInterface>& listener) const
 
 // --- NotifySwitchArgs ---
 
-NotifySwitchArgs::NotifySwitchArgs(nsecs_t eventTime, uint32_t policyFlags,
+NotifySwitchArgs::NotifySwitchArgs(uint32_t sequenceNum, nsecs_t eventTime, uint32_t policyFlags,
         uint32_t switchValues, uint32_t switchMask) :
-        eventTime(eventTime), policyFlags(policyFlags),
+        NotifyArgs(sequenceNum), eventTime(eventTime), policyFlags(policyFlags),
         switchValues(switchValues), switchMask(switchMask) {
 }
 
 NotifySwitchArgs::NotifySwitchArgs(const NotifySwitchArgs& other) :
-        eventTime(other.eventTime), policyFlags(other.policyFlags),
+        NotifyArgs(other.sequenceNum), eventTime(other.eventTime), policyFlags(other.policyFlags),
         switchValues(other.switchValues), switchMask(other.switchMask) {
 }
 
@@ -126,12 +127,13 @@ void NotifySwitchArgs::notify(const sp<InputListenerInterface>& listener) const
 
 // --- NotifyDeviceResetArgs ---
 
-NotifyDeviceResetArgs::NotifyDeviceResetArgs(nsecs_t eventTime, int32_t deviceId) :
-        eventTime(eventTime), deviceId(deviceId) {
+NotifyDeviceResetArgs::NotifyDeviceResetArgs(
+        uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId) :
+        NotifyArgs(sequenceNum), eventTime(eventTime), deviceId(deviceId) {
 }
 
 NotifyDeviceResetArgs::NotifyDeviceResetArgs(const NotifyDeviceResetArgs& other) :
-        eventTime(other.eventTime), deviceId(other.deviceId) {
+        NotifyArgs(other.sequenceNum), eventTime(other.eventTime), deviceId(other.deviceId) {
 }
 
 void NotifyDeviceResetArgs::notify(const sp<InputListenerInterface>& listener) const {
diff --git a/services/inputflinger/InputReader.cpp b/services/inputflinger/InputReader.cpp
index 9ba4140312..7e00f420cc 100644
--- a/services/inputflinger/InputReader.cpp
+++ b/services/inputflinger/InputReader.cpp
@@ -236,8 +236,8 @@ static void synthesizeButtonKey(InputReaderContext* context, int32_t action,
             || (action == AKEY_EVENT_ACTION_UP
                     && (lastButtonState & buttonState)
                     && !(currentButtonState & buttonState))) {
-        NotifyKeyArgs args(when, deviceId, source, displayId, policyFlags,
-                action, 0, keyCode, 0, context->getGlobalMetaState(), when);
+        NotifyKeyArgs args(context->getNextSequenceNum(), when, deviceId, source, displayId,
+                policyFlags, action, 0, keyCode, 0, context->getGlobalMetaState(), when);
         context->getListener()->notifyKey(&args);
     }
 }
@@ -261,7 +261,7 @@ InputReader::InputReader(const sp<EventHubInterface>& eventHub,
         const sp<InputReaderPolicyInterface>& policy,
         const sp<InputListenerInterface>& listener) :
         mContext(this), mEventHub(eventHub), mPolicy(policy),
-        mGlobalMetaState(0), mGeneration(1),
+        mNextSequenceNum(1), mGlobalMetaState(0), mGeneration(1),
         mDisableVirtualKeysTimeout(LLONG_MIN), mNextTimeout(LLONG_MAX),
         mConfigurationChangesToRefresh(0) {
     mQueuedListener = new QueuedInputListener(listener);
@@ -547,7 +547,7 @@ void InputReader::handleConfigurationChangedLocked(nsecs_t when) {
     updateGlobalMetaStateLocked();
 
     // Enqueue configuration changed.
-    NotifyConfigurationChangedArgs args(when);
+    NotifyConfigurationChangedArgs args(mContext.getNextSequenceNum(), when);
     mQueuedListener->notifyConfigurationChanged(&args);
 }
 
@@ -945,6 +945,9 @@ EventHubInterface* InputReader::ContextImpl::getEventHub() {
     return mReader->mEventHub.get();
 }
 
+uint32_t InputReader::ContextImpl::getNextSequenceNum() {
+    return (mReader->mNextSequenceNum)++;
+}
 
 // --- InputDevice ---
 
@@ -1265,7 +1268,7 @@ void InputDevice::bumpGeneration() {
 }
 
 void InputDevice::notifyReset(nsecs_t when) {
-    NotifyDeviceResetArgs args(when, mId);
+    NotifyDeviceResetArgs args(mContext->getNextSequenceNum(), when, mId);
     mContext->getListener()->notifyDeviceReset(&args);
 }
 
@@ -2038,7 +2041,8 @@ void SwitchInputMapper::processSwitch(int32_t switchCode, int32_t switchValue) {
 void SwitchInputMapper::sync(nsecs_t when) {
     if (mUpdatedSwitchMask) {
         uint32_t updatedSwitchValues = mSwitchValues & mUpdatedSwitchMask;
-        NotifySwitchArgs args(when, 0, updatedSwitchValues, mUpdatedSwitchMask);
+        NotifySwitchArgs args(mContext->getNextSequenceNum(), when, 0, updatedSwitchValues,
+                mUpdatedSwitchMask);
         getListener()->notifySwitch(&args);
 
         mUpdatedSwitchMask = 0;
@@ -2420,8 +2424,8 @@ void KeyboardInputMapper::processKey(nsecs_t when, bool down, int32_t scanCode,
         policyFlags |= POLICY_FLAG_DISABLE_KEY_REPEAT;
     }
 
-    NotifyKeyArgs args(when, getDeviceId(), mSource, getDisplayId(), policyFlags,
-            down ? AKEY_EVENT_ACTION_DOWN : AKEY_EVENT_ACTION_UP,
+    NotifyKeyArgs args(mContext->getNextSequenceNum(), when, getDeviceId(), mSource,
+            getDisplayId(), policyFlags, down ? AKEY_EVENT_ACTION_DOWN : AKEY_EVENT_ACTION_UP,
             AKEY_EVENT_FLAG_FROM_SYSTEM, keyCode, scanCode, keyMetaState, downTime);
     getListener()->notifyKey(&args);
 }
@@ -2824,7 +2828,8 @@ void CursorInputMapper::sync(nsecs_t when) {
             while (!released.isEmpty()) {
                 int32_t actionButton = BitSet32::valueForBit(released.clearFirstMarkedBit());
                 buttonState &= ~actionButton;
-                NotifyMotionArgs releaseArgs(when, getDeviceId(), mSource, displayId, policyFlags,
+                NotifyMotionArgs releaseArgs(mContext->getNextSequenceNum(), when, getDeviceId(),
+                        mSource, displayId, policyFlags,
                         AMOTION_EVENT_ACTION_BUTTON_RELEASE, actionButton, 0,
                         metaState, buttonState, AMOTION_EVENT_EDGE_FLAG_NONE,
                         /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
@@ -2833,8 +2838,8 @@ void CursorInputMapper::sync(nsecs_t when) {
             }
         }
 
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
-                motionEventAction, 0, 0, metaState, currentButtonState,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(), mSource,
+                displayId, policyFlags, motionEventAction, 0, 0, metaState, currentButtonState,
                 AMOTION_EVENT_EDGE_FLAG_NONE,
                 /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
                 mXPrecision, mYPrecision, downTime);
@@ -2845,9 +2850,9 @@ void CursorInputMapper::sync(nsecs_t when) {
             while (!pressed.isEmpty()) {
                 int32_t actionButton = BitSet32::valueForBit(pressed.clearFirstMarkedBit());
                 buttonState |= actionButton;
-                NotifyMotionArgs pressArgs(when, getDeviceId(), mSource, displayId, policyFlags,
-                        AMOTION_EVENT_ACTION_BUTTON_PRESS, actionButton, 0,
-                        metaState, buttonState, AMOTION_EVENT_EDGE_FLAG_NONE,
+                NotifyMotionArgs pressArgs(mContext->getNextSequenceNum(), when, getDeviceId(),
+                        mSource, displayId, policyFlags, AMOTION_EVENT_ACTION_BUTTON_PRESS,
+                        actionButton, 0, metaState, buttonState, AMOTION_EVENT_EDGE_FLAG_NONE,
                         /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
                         mXPrecision, mYPrecision, downTime);
                 getListener()->notifyMotion(&pressArgs);
@@ -2859,8 +2864,8 @@ void CursorInputMapper::sync(nsecs_t when) {
         // Send hover move after UP to tell the application that the mouse is hovering now.
         if (motionEventAction == AMOTION_EVENT_ACTION_UP
                 && (mSource == AINPUT_SOURCE_MOUSE)) {
-            NotifyMotionArgs hoverArgs(when, getDeviceId(), mSource, displayId, policyFlags,
-                    AMOTION_EVENT_ACTION_HOVER_MOVE, 0, 0,
+            NotifyMotionArgs hoverArgs(mContext->getNextSequenceNum(), when, getDeviceId(),
+                    mSource, displayId, policyFlags, AMOTION_EVENT_ACTION_HOVER_MOVE, 0, 0,
                     metaState, currentButtonState, AMOTION_EVENT_EDGE_FLAG_NONE,
                     /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
                     mXPrecision, mYPrecision, downTime);
@@ -2872,7 +2877,8 @@ void CursorInputMapper::sync(nsecs_t when) {
             pointerCoords.setAxisValue(AMOTION_EVENT_AXIS_VSCROLL, vscroll);
             pointerCoords.setAxisValue(AMOTION_EVENT_AXIS_HSCROLL, hscroll);
 
-            NotifyMotionArgs scrollArgs(when, getDeviceId(), mSource, displayId, policyFlags,
+            NotifyMotionArgs scrollArgs(mContext->getNextSequenceNum(), when, getDeviceId(),
+                    mSource, displayId, policyFlags,
                     AMOTION_EVENT_ACTION_SCROLL, 0, 0, metaState, currentButtonState,
                     AMOTION_EVENT_EDGE_FLAG_NONE,
                     /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
@@ -3003,7 +3009,8 @@ void RotaryEncoderInputMapper::sync(nsecs_t when) {
         int32_t metaState = mContext->getGlobalMetaState();
         pointerCoords.setAxisValue(AMOTION_EVENT_AXIS_SCROLL, scroll * mScalingFactor);
 
-        NotifyMotionArgs scrollArgs(when, getDeviceId(), mSource, displayId, policyFlags,
+        NotifyMotionArgs scrollArgs(mContext->getNextSequenceNum(), when, getDeviceId(),
+                mSource, displayId, policyFlags,
                 AMOTION_EVENT_ACTION_SCROLL, 0, 0, metaState, 0,
                 AMOTION_EVENT_EDGE_FLAG_NONE,
                 /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
@@ -4698,7 +4705,8 @@ void TouchInputMapper::dispatchVirtualKey(nsecs_t when, uint32_t policyFlags,
     int32_t metaState = mContext->getGlobalMetaState();
     policyFlags |= POLICY_FLAG_VIRTUAL;
 
-    NotifyKeyArgs args(when, getDeviceId(), AINPUT_SOURCE_KEYBOARD, mViewport.displayId,
+    NotifyKeyArgs args(mContext->getNextSequenceNum(), when, getDeviceId(), AINPUT_SOURCE_KEYBOARD,
+            mViewport.displayId,
             policyFlags, keyEventAction, keyEventFlags, keyCode, scanCode, metaState, downTime);
     getListener()->notifyKey(&args);
 }
@@ -5392,8 +5400,8 @@ void TouchInputMapper::dispatchPointerGestures(nsecs_t when, uint32_t policyFlag
         pointerCoords.setAxisValue(AMOTION_EVENT_AXIS_Y, y);
 
         int32_t displayId = mPointerController->getDisplayId();
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
-                AMOTION_EVENT_ACTION_HOVER_MOVE, 0, 0,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, displayId, mSource,
+                mViewport.displayId, policyFlags, AMOTION_EVENT_ACTION_HOVER_MOVE, 0, 0,
                 metaState, buttonState, AMOTION_EVENT_EDGE_FLAG_NONE,
                 /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
                 0, 0, mPointerGesture.downTime);
@@ -6317,7 +6325,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
         mPointerSimple.down = false;
 
         // Send up.
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                mSource, displayId, policyFlags,
                  AMOTION_EVENT_ACTION_UP, 0, 0, metaState, mLastRawState.buttonState, 0,
                  /* deviceTimestamp */ 0,
                  1, &mPointerSimple.lastProperties, &mPointerSimple.lastCoords,
@@ -6330,7 +6339,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
         mPointerSimple.hovering = false;
 
         // Send hover exit.
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                mSource, displayId, policyFlags,
                 AMOTION_EVENT_ACTION_HOVER_EXIT, 0, 0, metaState, mLastRawState.buttonState, 0,
                 /* deviceTimestamp */ 0,
                 1, &mPointerSimple.lastProperties, &mPointerSimple.lastCoords,
@@ -6345,7 +6355,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
             mPointerSimple.downTime = when;
 
             // Send down.
-            NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+            NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                    mSource, displayId, policyFlags,
                     AMOTION_EVENT_ACTION_DOWN, 0, 0, metaState, mCurrentRawState.buttonState, 0,
                     /* deviceTimestamp */ 0,
                     1, &mPointerSimple.currentProperties, &mPointerSimple.currentCoords,
@@ -6355,7 +6366,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
         }
 
         // Send move.
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                mSource, displayId, policyFlags,
                 AMOTION_EVENT_ACTION_MOVE, 0, 0, metaState, mCurrentRawState.buttonState, 0,
                 /* deviceTimestamp */ 0,
                 1, &mPointerSimple.currentProperties, &mPointerSimple.currentCoords,
@@ -6369,7 +6381,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
             mPointerSimple.hovering = true;
 
             // Send hover enter.
-            NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+            NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                    mSource, displayId, policyFlags,
                     AMOTION_EVENT_ACTION_HOVER_ENTER, 0, 0, metaState,
                     mCurrentRawState.buttonState, 0,
                     /* deviceTimestamp */ 0,
@@ -6380,7 +6393,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
         }
 
         // Send hover move.
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                mSource, displayId, policyFlags,
                 AMOTION_EVENT_ACTION_HOVER_MOVE, 0, 0, metaState,
                 mCurrentRawState.buttonState, 0,
                 /* deviceTimestamp */ 0,
@@ -6402,7 +6416,8 @@ void TouchInputMapper::dispatchPointerSimple(nsecs_t when, uint32_t policyFlags,
         pointerCoords.setAxisValue(AMOTION_EVENT_AXIS_VSCROLL, vscroll);
         pointerCoords.setAxisValue(AMOTION_EVENT_AXIS_HSCROLL, hscroll);
 
-        NotifyMotionArgs args(when, getDeviceId(), mSource, displayId, policyFlags,
+        NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+                mSource, displayId, policyFlags,
                 AMOTION_EVENT_ACTION_SCROLL, 0, 0, metaState, mCurrentRawState.buttonState, 0,
                 /* deviceTimestamp */ 0,
                 1, &mPointerSimple.currentProperties, &pointerCoords,
@@ -6466,7 +6481,8 @@ void TouchInputMapper::dispatchMotion(nsecs_t when, uint32_t policyFlags, uint32
     }
     int32_t displayId = mPointerController != nullptr ?
             mPointerController->getDisplayId() : mViewport.displayId;
-    NotifyMotionArgs args(when, getDeviceId(), source, displayId, policyFlags,
+    NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+            source, displayId, policyFlags,
             action, actionButton, flags, metaState, buttonState, edgeFlags,
             deviceTimestamp, pointerCount, pointerProperties, pointerCoords,
             xPrecision, yPrecision, downTime);
@@ -7390,8 +7406,8 @@ void JoystickInputMapper::sync(nsecs_t when, bool force) {
     // TODO: Use the input device configuration to control this behavior more finely.
     uint32_t policyFlags = 0;
 
-    NotifyMotionArgs args(when, getDeviceId(), AINPUT_SOURCE_JOYSTICK, ADISPLAY_ID_NONE,
-            policyFlags,
+    NotifyMotionArgs args(mContext->getNextSequenceNum(), when, getDeviceId(),
+            AINPUT_SOURCE_JOYSTICK, ADISPLAY_ID_NONE, policyFlags,
             AMOTION_EVENT_ACTION_MOVE, 0, 0, metaState, buttonState, AMOTION_EVENT_EDGE_FLAG_NONE,
             /* deviceTimestamp */ 0, 1, &pointerProperties, &pointerCoords,
             0, 0, 0);
diff --git a/services/inputflinger/InputReader.h b/services/inputflinger/InputReader.h
index 13f1bedb65..35f3c232c7 100644
--- a/services/inputflinger/InputReader.h
+++ b/services/inputflinger/InputReader.h
@@ -96,6 +96,8 @@ public:
     virtual InputReaderPolicyInterface* getPolicy() = 0;
     virtual InputListenerInterface* getListener() = 0;
     virtual EventHubInterface* getEventHub() = 0;
+
+    virtual uint32_t getNextSequenceNum() = 0;
 };
 
 
@@ -168,6 +170,7 @@ protected:
         virtual InputReaderPolicyInterface* getPolicy();
         virtual InputListenerInterface* getListener();
         virtual EventHubInterface* getEventHub();
+        virtual uint32_t getNextSequenceNum();
     } mContext;
 
     friend class ContextImpl;
@@ -183,6 +186,9 @@ private:
 
     InputReaderConfiguration mConfig;
 
+    // used by InputReaderContext::getNextSequenceNum() as a counter for event sequence numbers
+    uint32_t mNextSequenceNum;
+
     // The event queue.
     static const int EVENT_BUFFER_SIZE = 256;
     RawEvent mEventBuffer[EVENT_BUFFER_SIZE];
diff --git a/services/inputflinger/include/InputListener.h b/services/inputflinger/include/InputListener.h
index a3d919bf5a..f3a30ab684 100644
--- a/services/inputflinger/include/InputListener.h
+++ b/services/inputflinger/include/InputListener.h
@@ -28,6 +28,12 @@ class InputListenerInterface;
 
 /* Superclass of all input event argument objects */
 struct NotifyArgs {
+    uint32_t sequenceNum;
+
+    inline NotifyArgs() : sequenceNum(0) { }
+
+    inline explicit NotifyArgs(uint32_t sequenceNum) : sequenceNum(sequenceNum) { }
+
     virtual ~NotifyArgs() { }
 
     virtual void notify(const sp<InputListenerInterface>& listener) const = 0;
@@ -40,7 +46,7 @@ struct NotifyConfigurationChangedArgs : public NotifyArgs {
 
     inline NotifyConfigurationChangedArgs() { }
 
-    explicit NotifyConfigurationChangedArgs(nsecs_t eventTime);
+    NotifyConfigurationChangedArgs(uint32_t sequenceNum, nsecs_t eventTime);
 
     NotifyConfigurationChangedArgs(const NotifyConfigurationChangedArgs& other);
 
@@ -66,9 +72,9 @@ struct NotifyKeyArgs : public NotifyArgs {
 
     inline NotifyKeyArgs() { }
 
-    NotifyKeyArgs(nsecs_t eventTime, int32_t deviceId, uint32_t source, int32_t displayId,
-            uint32_t policyFlags, int32_t action, int32_t flags, int32_t keyCode, int32_t scanCode,
-            int32_t metaState, nsecs_t downTime);
+    NotifyKeyArgs(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId, uint32_t source,
+            int32_t displayId, uint32_t policyFlags, int32_t action, int32_t flags, int32_t keyCode,
+            int32_t scanCode, int32_t metaState, nsecs_t downTime);
 
     NotifyKeyArgs(const NotifyKeyArgs& other);
 
@@ -107,8 +113,8 @@ struct NotifyMotionArgs : public NotifyArgs {
 
     inline NotifyMotionArgs() { }
 
-    NotifyMotionArgs(nsecs_t eventTime, int32_t deviceId, uint32_t source, int32_t displayId,
-            uint32_t policyFlags,
+    NotifyMotionArgs(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId, uint32_t source,
+            int32_t displayId, uint32_t policyFlags,
             int32_t action, int32_t actionButton, int32_t flags,
             int32_t metaState, int32_t buttonState,
             int32_t edgeFlags, uint32_t deviceTimestamp, uint32_t pointerCount,
@@ -132,7 +138,7 @@ struct NotifySwitchArgs : public NotifyArgs {
 
     inline NotifySwitchArgs() { }
 
-    NotifySwitchArgs(nsecs_t eventTime, uint32_t policyFlags,
+    NotifySwitchArgs(uint32_t sequenceNum, nsecs_t eventTime, uint32_t policyFlags,
             uint32_t switchValues, uint32_t switchMask);
 
     NotifySwitchArgs(const NotifySwitchArgs& other);
@@ -151,7 +157,7 @@ struct NotifyDeviceResetArgs : public NotifyArgs {
 
     inline NotifyDeviceResetArgs() { }
 
-    NotifyDeviceResetArgs(nsecs_t eventTime, int32_t deviceId);
+    NotifyDeviceResetArgs(uint32_t sequenceNum, nsecs_t eventTime, int32_t deviceId);
 
     NotifyDeviceResetArgs(const NotifyDeviceResetArgs& other);
 
diff --git a/services/inputflinger/tests/InputReader_test.cpp b/services/inputflinger/tests/InputReader_test.cpp
index b18cae3e8f..855247f29d 100644
--- a/services/inputflinger/tests/InputReader_test.cpp
+++ b/services/inputflinger/tests/InputReader_test.cpp
@@ -853,13 +853,14 @@ class FakeInputReaderContext : public InputReaderContext {
     int32_t mGlobalMetaState;
     bool mUpdateGlobalMetaStateWasCalled;
     int32_t mGeneration;
+    uint32_t mNextSequenceNum;
 
 public:
     FakeInputReaderContext(const sp<EventHubInterface>& eventHub,
             const sp<InputReaderPolicyInterface>& policy,
             const sp<InputListenerInterface>& listener) :
             mEventHub(eventHub), mPolicy(policy), mListener(listener),
-            mGlobalMetaState(0) {
+            mGlobalMetaState(0), mNextSequenceNum(1) {
     }
 
     virtual ~FakeInputReaderContext() { }
@@ -923,6 +924,10 @@ private:
     virtual void dispatchExternalStylusState(const StylusState&) {
 
     }
+
+    virtual uint32_t getNextSequenceNum() {
+        return mNextSequenceNum++;
+    }
 };
 
 
@@ -1568,6 +1573,39 @@ TEST_F(InputReaderTest, LoopOnce_ForwardsRawEventsToMappers) {
     ASSERT_EQ(1, event.value);
 }
 
+TEST_F(InputReaderTest, DeviceReset_IncrementsSequenceNumber) {
+    constexpr int32_t deviceId = 1;
+    constexpr uint32_t deviceClass = INPUT_DEVICE_CLASS_KEYBOARD;
+    InputDevice* device = mReader->newDevice(deviceId, 0, "fake", deviceClass);
+    // Must add at least one mapper or the device will be ignored!
+    FakeInputMapper* mapper = new FakeInputMapper(device, AINPUT_SOURCE_KEYBOARD);
+    device->addMapper(mapper);
+    mReader->setNextDevice(device);
+    addDevice(deviceId, "fake", deviceClass, nullptr);
+
+    NotifyDeviceResetArgs resetArgs;
+    ASSERT_NO_FATAL_FAILURE(mFakeListener->assertNotifyDeviceResetWasCalled(&resetArgs));
+    uint32_t prevSequenceNum = resetArgs.sequenceNum;
+
+    disableDevice(deviceId, device);
+    mReader->loopOnce();
+    mFakeListener->assertNotifyDeviceResetWasCalled(&resetArgs);
+    ASSERT_TRUE(prevSequenceNum < resetArgs.sequenceNum);
+    prevSequenceNum = resetArgs.sequenceNum;
+
+    enableDevice(deviceId, device);
+    mReader->loopOnce();
+    mFakeListener->assertNotifyDeviceResetWasCalled(&resetArgs);
+    ASSERT_TRUE(prevSequenceNum < resetArgs.sequenceNum);
+    prevSequenceNum = resetArgs.sequenceNum;
+
+    disableDevice(deviceId, device);
+    mReader->loopOnce();
+    mFakeListener->assertNotifyDeviceResetWasCalled(&resetArgs);
+    ASSERT_TRUE(prevSequenceNum < resetArgs.sequenceNum);
+    prevSequenceNum = resetArgs.sequenceNum;
+}
+
 
 // --- InputDeviceTest ---