BTW, my X220 would not respond to the stylus (but it would to my finger) until I rotated the screen using the display settings. Once rotated to portrait mode, the stylus responded but not correctly, rather sending the mouse off as if the mouse's domain was still in landscape. Upon returning to landscape orientation, the stylus worked as it was supposed to. I have no explanation why this happened, but I rebooted the tablet multiple times before changing the orientation and always to no avail.
Using Oneiric as of December 30 2011, Fresh install, fully updated, no Xorg.conf file, just the stock software bundle as-is (new computer, fresh install).