Comment 13 for bug 762938

I have this problem too since upgrading to 11.04 which is a royal pain in the * when developing a tablet application in QT. The tablet is working fine as can be confirmed by using gtk apps so I don't think recording input events will be useful at all. This might be caused by an old issue - it used to be that QT had the names 'stylus', 'pen', and 'eraser' hardcoded into it. If the devices are called something else then QT just processes pen and eraser as mouse events hence no pressure information.

Ubuntu 9.04 renamed the wacom devices and broke the tablet events on QT but this could be fixed by rewriting the names using HAL. 10.10 worked fine but I have a mongrel of an installation.

If this is the cause then https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-evdev/+bug/721471 is a duplicate bug.