Prevent keyboards from being recognized as a stylus

We are getting reports of keyboards and other peripherals being
misconfigured as a stylus, because they report support for stylus
buttons.

To eliminate some of these misconfigurations, prevent anything detected
as a alphabetical keyboard from being categorized as a stylus.

Bug: 293996865
Test: None
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:3c28b94505b5c6edaeb7e0df3ace7cf3f8125887)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:0824e928e70da8c0fb78d9793a5a3f8f4f8f9db0)
Merged-In: I3f071d2ac6a2b70abc1130b4d5df1509452bb63b
Change-Id: I3f071d2ac6a2b70abc1130b4d5df1509452bb63b

2 files changed, 20 insertions, 1 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..a70f10b81c 100644
--- a/services/inputflinger/tests/InputReader_test.cpp
+++ b/services/inputflinger/tests/InputReader_test.cpp
@@ -1476,6 +1476,24 @@ 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());
+}
+
 /**
  * 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