Why is my device a touchpad and a mouse and a keyboard?
4 days ago
- #Kernel
- #Linux
- #HID
- HID devices under Linux often appear as multiple device nodes due to the kernel's HID implementation.
- The kernel splits devices based on Application Collections, applying usage-specific suffixes like 'Mouse', 'Keyboard', etc.
- Application Collections group HID functionalities, with types like 'Physical Collection' and 'Logical Collection'.
- Extra device nodes may never send events, sometimes due to device modes or vendor firmware reuse.
- This can cause user confusion or functional issues, like incorrect device detection by udev.
- Currently, the only solution is per-user udev rules to ignore fake devices.