http://bugs.winehq.org/show_bug.cgi?id=11846
--- Comment #8 from Dan Kegel dank@kegel.com 2008-03-15 16:05:27 --- Thanks for the log! It looks like wintab32 is happy with your device. I'm not sure why the pressure isn't coming through.
What model tablet are you using? Can you attach your /etc/X11/xorg.conf?
So to sum up, pressure works for you with Photoshop 7 and Artrage, but not with Sai or OpenCanvas?
(I posted about the Sai trial not for your benefit, but for anyone else looking at this bug.)