internal/gamepad: bug fix: ignore a device that doesn't have an appropriate button

internal/gamepad/api_linux.go

@@ -30,6 +30,16 @@ const (
 	_ABS_CNT   = _ABS_MAX + 1
 
 	_BTN_MISC = 0x100
+	_BTN_0    = 0x100
+	_BTN_1    = 0x101
+	_BTN_2    = 0x102
+	_BTN_3    = 0x103
+	_BTN_4    = 0x104
+	_BTN_5    = 0x105
+	_BTN_6    = 0x106
+	_BTN_7    = 0x107
+	_BTN_8    = 0x108
+	_BTN_9    = 0x109
 
 	_IOC_NONE  = 0
 	_IOC_WRITE = 1

internal/gamepad/gamepad_linux.go

@@ -181,13 +181,27 @@ func (*nativeGamepadsImpl) openGamepad(gamepads *gamepads, path string) (err err
 	var axisCount int
 	var buttonCount int
 	var hatCount int
+	var necessaryButtonExist bool
 	for code := _BTN_MISC; code < _KEY_CNT; code++ {
 		if !isBitSet(keyBits, code) {
 			continue
 		}
 		n.keyMap[code-_BTN_MISC] = buttonCount
+		if _BTN_0 <= code && code <= _BTN_9 {
+			necessaryButtonExist = true
+		}
 		buttonCount++
 	}
+
+	// If the device doesn't have any necessary bottons, this might not be a gamepad (#2039).
+	// Remove this.
+	if !necessaryButtonExist {
+		n.close()
+		gamepads.remove(func(gamepad *Gamepad) bool {
+			return gamepad == gp
+		})
+	}
+
 	for code := 0; code < _ABS_CNT; code++ {
 		n.absMap[code] = -1
 		if !isBitSet(absBits, code) {