1.. _tablet-debugging: 2 3============================================================================== 4Debugging tablet issues 5============================================================================== 6 7.. _tablet-capabilities: 8 9------------------------------------------------------------------------------ 10Required tablet capabilities 11------------------------------------------------------------------------------ 12 13To handle a tablet correctly, libinput requires a set of capabilities 14on the device. When these capabilities are missing, libinput ignores the 15device and prints an error to the log. This error messages reads 16 17:: 18 19 missing tablet capabilities: xy pen btn-stylus resolution. Ignoring this device. 20 21or in older versions of libinput simply: 22 23:: 24 25 libinput bug: device does not meet tablet criteria. Ignoring this device. 26 27 28When a tablet is rejected, it is usually possible to verify the issue with 29the ``libinput record`` tool. 30 31- **xy** indicates that the tablet is missing the ``ABS_X`` and/or ``ABS_Y`` 32 axis. This indicates that the device is mislabelled and the udev tag 33 ``ID_INPUT_TABLET`` is applied to a device that is not a tablet. 34 A bug should be filed against `systemd <http://github.com/systemd/systemd>`__. 35- **pen** or **btn-stylus** indicates that the tablet does not have the 36 ``BTN_TOOL_PEN`` or ``BTN_STYLUS`` bit set. libinput requires either or both 37 of them to be present. This indicates a bug in the kernel driver 38 or the HID descriptors of the device. 39- **resolution** indicates that the device does not have a resolution set 40 for the x and y axes. This can be fixed with a hwdb entry, locate and read 41 the `60-evdev.hwdb 42 <https://github.com/systemd/systemd/blob/main/hwdb.d/60-evdev.hwdb>`__ file 43 on your machine and file a pull request with the fixes against 44 `systemd <https://github.com/systemd/systemd/>`__. 45