Overview

libwacom is a library to identify Wacom tablets and their model-specific features. It provides easy access to information such as "is this a built-in on-screen tablet", "what is the size of this model", etc.

This functionality is currently used by e.g. GNOME to map built-in tablets to the correct screen.

Adding tablet descriptions to libwacom

A common indicator that a device is not supported by libwacom is that it works normally in a GNOME session, but the device is not correctly mapped to the screen.

Use the libwacom-list-local-devices tool to list all local devices recognized by libwacom. If your device is not listed, but it is available as an event device in the kernel (see /proc/bus/input/devices) and in the X session (see xinput list), the device is missing from libwacom's database.

To add support for a new tablet to libwacom git:

1. Create a new tablet definition file. See data/wacom.example in the source for a guideline on how to add a new tablet. For an installed version of libwacom, see the existing data files (e.g. /usr/share/libwacom/cintiq-13hd.tablet)
2. A new tablet description is enabled by adding and installing a new file with a .tablet suffix. Once installed the tablet is part of libwacom's database, no rebuild is neccessary
3. The tablet is then available through libwacom-list-local-devices

You must update udev after installing the file, see below.

To add support for a tablet to an older libwacom

If the system-provided libwacom does not include a .tablet file, it is possible to "backport" that .tablet file to the system-provided libwacom. Simply copy the .tablet file from the upstream git tree into the local directory /etc/libwacom/. Create that directory if necessary.

For versions of libwacom older than 1.9, the file should be copied to /usr/share/libwacom. It may be overwritten on updates.

You must update udev after installing the file, see below.

Updating udev's hwdb

The new device must be added to the udev hwdb to ensure all required udev properties are set. Without a hwdb entry, the device may not be detected as tablet and may not work correctly.

When building from source

Generate an updated hwdb with tools/generate-hwdb.py after adding the tablet description to the data/ directory. This is done automatically during the build, look for the 65-libwacom.hwdb file in the build tree. This file is installed as part of ninja install or make install. Run the following command to activate the new hwdb set:

$ sudo systemd-hwdb update

Now disconnect and reconnect the device and it should be detected by libwacom.

When adding files to an installed version of libwacom

After installing the .tablet file in /etc/libwacom/, run the generate-hwdb.py tool: This tool can be run from the source tree.

$ generate-hwdb.py /etc/libwacom > 66-libwacom-local.hwdb
$ sudo cp 66-libwacom-local.hwdb /etc/udev/hwdb.d/
$ sudo systemd-hwdb update

Now disconnect and reconnect the device and it should be detected by libwacom.