Comment # 11 on bug 1120405 from Takashi Iwai

(In reply to Tobias Havla from comment #9)
> I've managed to get the serial Wacom tablet working under Xorg (looked at
> the Xorg.0.log wacom error). I've added myself to the dialout group (see
> attached contents of /dev/) and after a relogin the digitizer and
> touchscreen are working fine. I don't know if this is intentional, but even
> if it is, it should be documented somewhere.

Thanks for spotting out.  So the X problem looks like a device permission
issue.
Maybe we need to put uaccess tag to these devices in udev rules.