Description:
On the update to newer Xorg server and related components (see below) the tablet calibration was thrown off. Left-right was still fine, but the vertical scale was off. At the top of the screen stylus and cursor agreed, but they became progressively more separated as the cursor moves down. With the stylus at the bottom edge, the cursor was still only about 3/4s of the way down.


Additional info:
* package version(s)
The broken packages were:
xorg-server-1.4.2-1-i686.pkg.tar.gz
xorg-server-utils-7.3-1-i686.pkg.tar.gz
xorg-utils-7.3-1-i686.pkg.tar.gz
xorg-xinit-1.1.0-1-i686.pkg.tar.gz

and the old versions that work are:
xorg-server-1.4.0.90-13-i686.pkg.tar.gz
xorg-server-utils-1.0.4-2.pkg.tar.gz
xorg-utils-1.0.2-4.pkg.tar.gz
xorg-xinit-1.0.7-3-i686.pkg.tar.gz

I've attached the new and old Xorg.log files. I grepped both for -i wacom and found that the lines are actually different. The relevant sections seem to be:

A working one:
(==) Wacom using pressure threshold of 15 for button 1
(==) Wacom General ISDV4 tablet speed=9600 (19200) maxX=24570 maxY=18428 maxZ=255 resX=2540 resY=2540 tilt=disabled
(==) Wacom device "cursor" top X=0 top Y=0 bottom X=24570 bottom Y=18428 resol X=2540 resol Y=2540
(==) Wacom device "eraser" top X=0 top Y=0 bottom X=24570 bottom Y=18428 resol X=2540 resol Y=2540
(==) Wacom device "stylus" top X=0 top Y=0 bottom X=24570 bottom Y=18428 resol X=2540 resol Y=2540

With the old log, we see some thus:
(==) Wacom using pressure threshold of 15 for button 1
(==) Wacom General ISDV4 tablet speed=9600 (19200) maxX=24570 maxY=18428 maxZ=255 resX=2540 resY=2540 tilt=disabled
(==) Wacom device "cursor" top X=0 top Y=0 bottom X=24570 bottom Y=18428 resol X=2540 resol Y=2540
(==) Wacom device "eraser" top X=0 top Y=0 bottom X=24570 bottom Y=18428 resol X=2540 resol Y=2540
(==) Wacom device "stylus" top X=0 top Y=0 bottom X=24570 bottom Y=18428 resol X=2540 resol Y=2540

which match the working one. Then, it switches to
(==) Wacom General ISDV4 tablet speed=9600 (19200) maxX=24570 maxY=18428 maxZ=255 resX=2540 resY=2540 tilt=disabled
(==) Wacom device "cursor" top X=0 top Y=0 bottom X=18428 bottom Y=24570 resol X=2540 resol Y=2540
(==) Wacom device "eraser" top X=0 top Y=0 bottom X=18428 bottom Y=24570 resol X=2540 resol Y=2540
(==) Wacom device "stylus" top X=0 top Y=0 bottom X=18428 bottom Y=24570 resol X=2540 resol Y=2540

which seems to be backwards (screen rotation?), and finally to
(==) Wacom General ISDV4 tablet speed=9600 (19200) maxX=24570 maxY=18428 maxZ=255 resX=2540 resY=2540 tilt=disabled
(==) Wacom device "cursor" top X=0 top Y=0 bottom X=24570 bottom Y=24570 resol X=2540 resol Y=2540
(==) Wacom device "eraser" top X=0 top Y=0 bottom X=24570 bottom Y=24570 resol X=2540 resol Y=2540
(==) Wacom device "stylus" top X=0 top Y=0 bottom X=24570 bottom Y=24570 resol X=2540 resol Y=2540

which seems to be just wrong.


Steps to reproduce:
1. Have a tablet PC with a Wacom serial tablet.
2. Update to the newest Xorg packages.
3. Try the stylus.

This is worked around for the present, since I've downgraded to the old, working Xorg.