I have installed xorg from Debian unstable on a Stylistic 2300 (active pen).

Without the "Passive" option in xorg.conf, the cursor moves fine, but sends no
button events. 

However, the buttons do work in the bios configuration menus, and running the
simplepen test program in a text console
(http://nocat.net/download/contrib/simplepen.c) also reports both buttons as
working. It is also very useful for pen calibration!

I believe the problem lies somewhere in the following bits of code from the
xf86Fpit.c:

    #define PROXIMITY_BIT	0x20 /* DMC: This was 0x40 but the chart says its bit
5 which is 0x20 */

Maybe it should be 0x40 after all, at least for some models of Stylistic (or
maybe not - see below).

So we would be using the wrong bit to set the variable prox (or setting it
backwards?):

  prox = (priv->fpitData[loop] & PROXIMITY_BIT) ? 0 : 1;

And when we test proximity for non-passive pens, since prox might be set
incorrectly, we assume we are in hover mode when we are not, and the buttons are
always reset to 0 and never get processed:

    if (priv->fpitPassive) {
	.......
    else { /* the active pen's buttons map directly to the mouse buttons */
			if (!prox) buttons=0; /* We are in hover mode, so no buttons */

I have also tried setting the "Passive" option in xorg.conf, with very strange
results.

I do get click events, but not when I bring the pen towards the screen, as one
might expect, but when I pull it away, as if the proximity bit were inverted.
The side button on the stylus also works - but again only if I keep the pen at
certain distance from the screen.

So the bug definitely has to do with mis-reading or mis-interpreting the
proximity bit.

Many thanks,
Marcos