4 files changed, 72 insertions, 2 deletions

diff --git a/services/inputflinger/reader/EventHub.cpp b/services/inputflinger/reader/EventHub.cpp
index 0354164155..c468d45c02 100644
--- a/services/inputflinger/reader/EventHub.cpp
+++ b/services/inputflinger/reader/EventHub.cpp
@@ -2409,7 +2409,8 @@ void EventHub::openDeviceLocked(const std::string& devicePath) {
         }
 
         // See if this device has any stylus buttons that we would want to fuse with touch data.
-        if (!device->classes.any(InputDeviceClass::TOUCH | InputDeviceClass::TOUCH_MT)) {
+        if (!device->classes.any(InputDeviceClass::TOUCH | InputDeviceClass::TOUCH_MT) &&
+            !device->classes.any(InputDeviceClass::ALPHAKEY)) {
             for (int32_t keycode : STYLUS_BUTTON_KEYCODES) {
                 if (device->hasKeycodeLocked(keycode)) {
                     device->classes |= InputDeviceClass::EXTERNAL_STYLUS;
diff --git a/services/inputflinger/tests/InputReader_test.cpp b/services/inputflinger/tests/InputReader_test.cpp
index 5141acb5b9..38b32b3632 100644
--- a/services/inputflinger/tests/InputReader_test.cpp
+++ b/services/inputflinger/tests/InputReader_test.cpp
@@ -1476,6 +1476,46 @@ TEST_F(InputReaderIntegrationTest, ExternalStylusesButtons) {
             AllOf(UP, WithKeyCode(AKEYCODE_STYLUS_BUTTON_TERTIARY))));
 }
 
+TEST_F(InputReaderIntegrationTest, KeyboardWithStylusButtons) {
+    std::unique_ptr<UinputKeyboard> keyboard =
+            createUinputDevice<UinputKeyboard>("KeyboardWithStylusButtons", /*productId=*/99,
+                                               std::initializer_list<int>{KEY_Q, KEY_W, KEY_E,
+                                                                          KEY_R, KEY_T, KEY_Y,
+                                                                          BTN_STYLUS, BTN_STYLUS2,
+                                                                          BTN_STYLUS3});
+    ASSERT_NO_FATAL_FAILURE(mFakePolicy->assertInputDevicesChanged());
+
+    const auto device = findDeviceByName(keyboard->getName());
+    ASSERT_TRUE(device.has_value());
+
+    // An alphabetical keyboard that reports stylus buttons should not be recognized as a stylus.
+    ASSERT_EQ(AINPUT_SOURCE_KEYBOARD, device->getSources())
+            << "Unexpected source " << inputEventSourceToString(device->getSources()).c_str();
+    ASSERT_EQ(AINPUT_KEYBOARD_TYPE_ALPHABETIC, device->getKeyboardType());
+}
+
+TEST_F(InputReaderIntegrationTest, HidUsageKeyboardIsNotAStylus) {
+    // Create a Uinput keyboard that simulates a keyboard that can report HID usage codes. The
+    // hid-input driver reports HID usage codes using the value for EV_MSC MSC_SCAN event.
+    std::unique_ptr<UinputKeyboardWithHidUsage> keyboard =
+            createUinputDevice<UinputKeyboardWithHidUsage>(
+                    std::initializer_list<int>{KEY_VOLUMEUP, KEY_VOLUMEDOWN});
+    ASSERT_NO_FATAL_FAILURE(mFakePolicy->assertInputDevicesChanged());
+
+    const auto device = findDeviceByName(keyboard->getName());
+    ASSERT_TRUE(device.has_value());
+
+    ASSERT_EQ(AINPUT_SOURCE_KEYBOARD, device->getSources())
+            << "Unexpected source " << inputEventSourceToString(device->getSources()).c_str();
+
+    // If a device supports reporting HID usage codes, it shouldn't automatically support
+    // stylus keys.
+    const std::vector<int> keycodes{AKEYCODE_STYLUS_BUTTON_PRIMARY};
+    uint8_t outFlags[] = {0};
+    ASSERT_TRUE(mReader->hasKeys(device->getId(), AINPUT_SOURCE_KEYBOARD, keycodes, outFlags));
+    ASSERT_EQ(0, outFlags[0]) << "Keyboard should not have stylus button";
+}
+
 /**
  * The Steam controller sends BTN_GEAR_DOWN and BTN_GEAR_UP for the two "paddle" buttons
  * on the back. In this test, we make sure that BTN_GEAR_DOWN / BTN_WHEEL and BTN_GEAR_UP
diff --git a/services/inputflinger/tests/UinputDevice.cpp b/services/inputflinger/tests/UinputDevice.cpp
index 97a26141e0..5a654c907d 100644
--- a/services/inputflinger/tests/UinputDevice.cpp
+++ b/services/inputflinger/tests/UinputDevice.cpp
@@ -157,6 +157,18 @@ void UinputExternalStylusWithPressure::setPressure(int32_t pressure) {
     injectEvent(EV_SYN, SYN_REPORT, 0);
 }
 
+// --- UinputKeyboardWithHidUsage ---
+
+UinputKeyboardWithHidUsage::UinputKeyboardWithHidUsage(std::initializer_list<int> keys)
+      : UinputKeyboard(DEVICE_NAME, PRODUCT_ID, keys) {}
+
+void UinputKeyboardWithHidUsage::configureDevice(int fd, uinput_user_dev* device) {
+    UinputKeyboard::configureDevice(fd, device);
+
+    ioctl(fd, UI_SET_EVBIT, EV_MSC);
+    ioctl(fd, UI_SET_MSCBIT, MSC_SCAN);
+}
+
 // --- UinputTouchScreen ---
 
 UinputTouchScreen::UinputTouchScreen(const Rect& size)
diff --git a/services/inputflinger/tests/UinputDevice.h b/services/inputflinger/tests/UinputDevice.h
index 51e331df8f..55996b8bfe 100644
--- a/services/inputflinger/tests/UinputDevice.h
+++ b/services/inputflinger/tests/UinputDevice.h
@@ -165,13 +165,30 @@ private:
     explicit UinputExternalStylusWithPressure();
 };
 
+// --- UinputKeyboardWithUsage ---
+// A keyboard that supports EV_MSC MSC_SCAN through which it can report HID usage codes.
+
+class UinputKeyboardWithHidUsage : public UinputKeyboard {
+public:
+    static constexpr const char* DEVICE_NAME = "Test Uinput Keyboard With Usage";
+    static constexpr int16_t PRODUCT_ID = 47;
+
+    template <class D, class... Ts>
+    friend std::unique_ptr<D> createUinputDevice(Ts... args);
+
+protected:
+    explicit UinputKeyboardWithHidUsage(std::initializer_list<int> keys);
+
+    void configureDevice(int fd, uinput_user_dev* device) override;
+};
+
 // --- UinputTouchScreen ---
 
 // A multi-touch touchscreen device with specific size that also supports styluses.
 class UinputTouchScreen : public UinputKeyboard {
 public:
     static constexpr const char* DEVICE_NAME = "Test Uinput Touch Screen";
-    static constexpr int16_t PRODUCT_ID = 47;
+    static constexpr int16_t PRODUCT_ID = 48;
 
     static const int32_t RAW_TOUCH_MIN = 0;
     static const int32_t RAW_TOUCH_MAX = 31;