1 files changed, 33 insertions, 0 deletions
diff --git a/device/bluetooth/bluetooth_device.cc b/device/bluetooth/bluetooth_device.cc
index c85af11..5696632 100644
--- a/device/bluetooth/bluetooth_device.cc
+++ b/device/bluetooth/bluetooth_device.cc
@@ -171,6 +171,39 @@ BluetoothDevice::DeviceType BluetoothDevice::GetDeviceType() const {
       break;
   }
 
+  // Some bluetooth devices, e.g., Microsoft Universal Foldable Keyboard,
+  // do not expose its bluetooth class. Use its appearance as a work-around.
+  // https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.gap.appearance.xml
+  uint16_t appearance = GetAppearance();
+  // appearance: 10-bit category and 6-bit sub-category
+  switch ((appearance & 0xffc0) >> 6) {
+    case 0x01:
+      // Generic phone
+      return DEVICE_PHONE;
+    case 0x02:
+      // Generic computer
+      return DEVICE_COMPUTER;
+    case 0x0f:
+      // HID subtype
+      switch (appearance & 0x3f) {
+        case 0x01:
+          // Keyboard.
+          return DEVICE_KEYBOARD;
+        case 0x02:
+          // Mouse
+          return DEVICE_MOUSE;
+        case 0x03:
+          // Joystick
+          return DEVICE_JOYSTICK;
+        case 0x04:
+          // Gamepad
+          return DEVICE_GAMEPAD;
+        case 0x05:
+          // Digitizer tablet
+          return DEVICE_TABLET;
+      }
+  }
+
   return DEVICE_UNKNOWN;
 }