WACOM Theory of operation

2013-07-13
2013-07-14
  • This site is great, and it's awesome to see the open source community help
    out. However, I have to point out that the Windows "How Wacom tablets
    work" isn't correct.

    Here's the of gist what it is (at least for the Intuos and Cintiq lines):

    When you buy a USB Wacom tablet, Wacom has two collections pre-loaded: a
    mouse and a Generic Digitizer collection. In the digitizer collection, at
    the usages, max, mins, etc., are blanked out. This is why Windows doesn't
    recognize the information, it doesn't know how to handle the data unless
    the Wacom drivers come in as middleware to do conversion and reporting.
    Also, it's reported in Big Endian format.

    I determined this by unloading my Wacom software and then using USBlyzer to
    check out the DTK-2100's Report Descriptors. To verify that users don't
    actually need the Wacom drivers on windows, I made a lightweight HID driver
    for the DTK-2100, and my Wacom stylus worked fine. I'm still implementing
    the ExpressKeys / Touchstrips.

    Just to recap, the issue is with the baked-in Intuos/Cintiq Report
    Descriptor, not the Windows HID subsystem.

    Thanks for this maintaining linuxwacom, it was a invaluable resource when I
    was programming the Windows Wacom HID driver!

    Kind regards,

    --
    Will Jones