Linux 5.20 To Support The XP-PEN Deco L Drawing Tablet

The XP-PEN Deco L is a recently launched graphics drawing tablet with its Linux support backed by a user-space binary blob package. But thanks to some USB reverse engineering from a community developer and discovering the hardware's "magic data" needed for initialization, this drawing tablet will be supported by a proper kernel driver in the next Linux kernel cycle.

The official XP-PEN Linux driver remains a binary-only package with a generic tarball as well as a Debian and RPM package shipping a user-space "pentablet" binary for supporting these USB-based tablets. The user-space package is limited to x86_64 and ships its own Qt5 libraries and XP-PEN's Linux support is designed to just support GIMP and Darktable. It's a sad state for Linux driver support in 2022 and more akin to the spotty IHV Linux support from two decades ago.

The official user-space binary package...

Thankfully José Expósito has managed to reverse-engineer support for the XP-PEN Deco L into the "uclogic" Linux HID driver to provide a proper kernel driver for these new drawing tablets. The uclogic kernel driver has supported prior XP-PEN tablets but special handling is needed for the Deco L.

The magic data.

Expósito commented in the patch now in HID for-next: "The XP-PEN Deco L (UGEE) needs to be initialized by sending a buffer of magic data, discovered by sniffing the Windows driver traffic...After initialization, the template report descriptors can be discovered by parsing a string descriptor, similar to the one exposed by HUION v1 devices. Add all the required elements to support the device."

XP-PEN Deco L models

With that patch in HID's for-next Git branch, it's material for the Linux 5.20 cycle later this summer. The XP-PEN Deco L is a 10 x 6 inch drawing tablet and pricing starts at $69.99.