Introduction

This HOWTO is intended to help you fix problems related to Ubuntu and the Asus R1E Tablet PC. This HOWTO may be applicable to other models, such as the Asus R1F, where hardware specs overlap.

Currently, this HOWTO only deals with the tablet function of the Asus R1E.

Enabling tablet functionality

This section will guide you through updating and configuring the latest wacom development drivers, which include support for USB-based Tablet PCs. If the tablet function is already working properly, then you can skip this section. If you are having issues with the tablet, check the Troubleshooting and known issues section.

Installing required packages

Ubuntu 10.04

Nearly everything works out of the box in this version. However, there is still an issue with tablet coordinates when rotating the screen. To fix this, you can use the patch found under the Rotate Screen section.

Updating xorg.conf

Enable "rotate screen" functionality

Ubuntu 10.04

Rotating the screen coordinates is done by /etc/acpi/rotatescreen.sh. Getting the tablet coordinates to sync with the screen coordinates is just a matter of calling xsetwacom with the appropriate parameters from that script. The following patch updates rotatescreen.sh for you.

*** /etc/acpi/rotatescreen.sh.orig      2010-07-24 16:38:17.026053835 +0200
--- /etc/acpi/rotatescreen.sh   2010-07-24 16:38:03.588544839 +0200
***************
*** 26,31 ****
--- 26,43 ----
        if [ x"$XAUTHORITY" != x"" ]; then
            export DISPLAY=":$displaynum"           
            /usr/bin/xrandr -o $NEW_ROTATION && echo $NEW_ROTATION > /var/lib/acpi-support/screen-rotation
+           OIFS=$IFS
+           IFS='
+ '
+           WACOMDEVICES=`xsetwacom --list | awk NF--`
+           for device in $WACOMDEVICES; do
+               if [ "$NEW_ROTATION" = "normal" ]; then
+                   xsetwacom set "$device" rotate NONE
+               else
+                   xsetwacom set "$device" rotate CW
+               fi
+           done
+           IFS=$OIFS
        fi
  done

To patch the file, simply save the patch, say, in your home directory as "rotatescreen.patch", and issue the following command (make sure that the current directory is the same as where you saved the patch):

sudo patch -p0 -i rotatescreen.patch

The patched script asks xsetwacom for a list of devices, removing the last word from each of them (as it's not part of the device name), and sets their rotation according to the screen rotation. Of course, if you don't want to rotate every device xsetwacom reports, you can simply replace the for-loop with hard coded calls to xsetwacom.

Troubleshooting and known issues

Jitter

If the pen is producing jagged lines (jitter), try compiling with or without the "--disable-quirk-tablet-rescale" flag. If the jitter is due to the pen being too sensitive (shaky hand), try playing with the "Suppress" option, which takes a value between 0 and 100. Keep in mind that while a high value will reduce jitter, it will also reduce accuracy.

Update it directly without restarting X:

xsetwacom set stylus Suppress value
xsetwacom set eraser Suppress value

When you've found a good value, add it to each wacom InputDevice section of xorg.conf to make it permanent:

        Option          "Suppress"          "value"

Missing functionality

The tablet ctrl-alt-del button isn't working. This appears to be because it's sending "left ctrl+left alt+KP delete", which isn't mapped to any specific action.

Applications

Some applications require that you set up the tablet as a valid input device, in order to use some tablet specific features, such as pressure sensitivity.

For use with the GIMP, you have to enable the stylus and eraser in the GIMP: File->Preferences->Input Devices->Configure Extended Input Devices..., select stylus and eraser, and set Mode to Screen.

GIMP doesn't appear to update the in-program cursor position when rotating the screen. If the tablet input is off, restart GIMP while the screen is rotated the way you want.

Xournal may produce jagged lines, even if the tablet works fine in other applications. If so, try switching "Discard Core Events" on and off, when "Use XInput" is checked.

Useful applications

The GIMP

Image Manipulation Program.

Supports pressure sensitivity from tablet input if enabled.

Xournal

Note taking application.

Useful for taking notes or making quick notes. Uses vector graphics to store input.

CellWriter

Handwriting recognition software.

Handwriting input with support for most unicode characters. Also has a normal click-based keyboard function.

CategoryHardware