Debugging tablet issues¶
Required tablet capabilities¶
To handle a tablet correctly, libinput requires a set of capabilities on the device. When these capabilities are missing, libinput ignores the device and prints an error to the log. This error messages reads
missing tablet capabilities: xy pen btn-stylus resolution. Ignoring this device.
or in older versions of libinput simply:
libinput bug: device does not meet tablet criteria. Ignoring this device.
When a tablet is rejected, it is usually possible to verify the issue with
the libinput record
tool.
xy indicates that the tablet is missing the
ABS_X
and/orABS_Y
axis. This indicates that the device is mislabelled and the udev tagID_INPUT_TABLET
is applied to a device that is not a tablet. A bug should be filed against systemd.pen or btn-stylus indicates that the tablet does not have the
BTN_TOOL_PEN
orBTN_STYLUS
bit set. libinput requires either or both of them to be present. This indicates a bug in the kernel driver or the HID descriptors of the device.resolution indicates that the device does not have a resolution set for the x and y axes. This can be fixed with a hwdb entry, locate and read the 60-evdev.hwdb file on your machine and file a pull request with the fixes against systemd.