Panasonic ToughBook CF-18 touchscreen issues

Mart van de Wege mvdwege at
Sat May 3 04:55:33 PDT 2008


I happen to have acquired a ToughBook CF-18 convertible
Notebook/Tablet. It's the Mark I hardware revision, so it uses a
Fujitsu/Siemens touchscreen, not a Wacom-compatible digitizer.

The touchscreen is the only component not working correctly:

1. Using evtouch, the calibrate script seems to work OK, and outputs
   values that look sane to me. However, deactivating the "Calibrate
   "1"" option and starting the X-server, my cursor jumps around in a
   seemingly random manner. Even if it would work, following the
   official instructions means I can't use a USB mouse or the touchpad
   in parallel, as the evtouch maintainer suggests loading the 'void'
   driver for the mouse.

2. Using evdev, the cursor tracks perfectly well until I hit the edges
   of the screen, then the cursor keeps hanging some tens of pixels
   away from the edge.

I would prefer to get evdev working, as I then can keep using a mouse
or the touchpad in parallel. It would appear that I need to adjust
some things to map the output from evdev (which gives 60,60 as the
origin and 965,965 as the lower right corner[1]) to actual screen
coordinates. However, googling and reading the manpage for evdev gives
me no suggestion as to where to set the parameters to calibrate the

The driver source seems to suggest that there is a mapping from
absolute evdev axis events to X-Input Absolute axis events.

How do I proceed to calibrate my touchscreen?

I'd be willing to provide documentation patches if I get a working


[1] values are approximate.

"We will need a longer wall when the revolution comes."
--- AJS, quoting an uncertain source.

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