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Linux Wacom Project HOWTO

4.0 - Viewing Wacom Data (wacdump)






The wacdump program parses and displays raw data from the Linux event subsystem or serial port. It is very handy for verifying that your tablet works without having to hassle with X server. Generally, you must be root to run it unless you've set the permissions on the appropriate device such that you can read them.

Running wacdump

In the case of USB tablets, this program can run simultaneously with X, but it's best if X has not been configured for the tablet yet. X will not share the serial port with wacdump, so serial users should comment out the wacom InputDevice sections from XF86Config (or xorg.conf) before using. Alternatively, you could move your serial tablet to COM2 and try /dev/ttyS1 instead.

Note: 1. Patrick Horgan pointed out that on some systems, issuing wacdump while X is running, wacdump crashes. Launching wacdump from a console by resolves the problem. 2. David Foley mentioned that some serial tablet users who run the serial patches for xf86-input-wacom need to run wacdump briefly after X started. Otherwise the tablet won't initialize.

The command line usage of wacdump is pretty simple:

Usage: wacdump [options] device
Options:
  -h, --help               - usage
  -c, --class device_cls   - use specified class (see below)
  -f, --force device_name  - use specified device (see below)
  -l, --list               - list all supported devices
  -v, --verbose            - increase log output; multiple OK
  -V, --version            - display version number
  --logfile log_file       - output log to file

Example devices:
  /dev/input/event0        - usb tablet device
  /dev/ttyS0               - serial tablet on com1
  /dev/ttyUSB0             - serial tablet on USB adapter

Supported device classes:
  serial, usb
Supported device names:
  serial: art, art2, dig, dig2, pp, gr, pl, int, int2, c100
  usb: pp, gr, gr2, int, int2, pl, vol

Older versions of wacdump assumed the device to be /dev/input/event0. This is now deprecated. You should instead specify which device to use on the command line directly. If you get an end-of-file error or the device does not exist, then the wacom may be attached to a different event. Serial users may experience a timeout error which indicates that either the tablet is not responding or X server has it open. Access denied errors probably indicate that you are not root. If you get different types of errors, let me know so we can get them documented.

Serial users are advised that now is a good time to plug in your tablet, if you haven't already.

Let's run wacdump. Here are some command line examples:

[jej@ayukawa src]$ ./wacdump /dev/input/event0        # typical USB tablet
[jej@ayukawa src]$ ./wacdump /dev/input/event1        # USB tablet on event1

When you run wacdump, it will attempt to initialize and query the tablet. For a number of reasons, it may not display anything immediately, but if you place a mouse or pen near the surface, the screen should update. You will then be presented with a screen similar to the following:

wacdump v0.4.0
MODEL=Wacom Intuos2 12x12               ROM=1.1-5
CLS=USB  VNDR=Wacom  DEV=Intuos2  SUB=XD-1212-U

TOOLTYPE=NONE                             SERIAL=0x00000000
 IN_PROX=+00000 (+00000 .. +00000)        BUTTON=+00000 (+00000 .. +00000)
   POS_X=+00000 (+00000 .. +30480)         POS_Y=+00000 (+00000 .. +31680)
   ROT_Z=+00000 (-00900 .. +00899)      DISTANCE=+00000 (+00000 .. +00015)
PRESSURE=+00000 (+00000 .. +01023)        TILT_X=+00000 (+00000 .. +00127)
  TILT_Y=+00000 (+00000 .. +00127)      ABSWHEEL=+00000 (+00000 .. +01023)
RELWHEEL=+00000 (-00001 .. +00001)      THROTTLE=+00000 (-01023 .. +01023)

    LEFT=             MIDDLE=              RIGHT=              EXTRA=
    SIDE=              TOUCH=             STYLUS=            STYLUS2=

The top portion identifies the tablet, and unless you specifically override the device type with the -f option, it should be auto-detected from the tablet directly. In this case, the model is XD-1212-U, a USB Intuos2 12x12.

The next section describes the dynamic attributes of the tablet, including the current position of the pointer, the type of tool in proximity to the surface, its pressure, and tilt. Some tablets (Protocol V tablets, such as Intuos 1, 2, and 3 as well as Cintiq 21UX) provide serial numbers for their tools. When a button is pressed, the button heading will change to something like "STYLUS=DOWN".

Some tablet tools report wheel movements as single increments forward and reverse, while others provide absolute positions. The 4D mouse has a throttle instead of a wheel. All three cases are reported independently.

Different tablets will have different options. Here is the lowly ArtPadII for comparison.

wacdump v0.4.0
MODEL=Wacom ArtPadII 4x5                ROM=1.3-6
CLS=Serial  VNDR=Wacom  DEV=ArtPadII  SUB=KT-0405-R

TOOLTYPE=NONE                            IN_PROX=+00000 (+00000 .. +00000)
  BUTTON=+00000 (+00000 .. +00000)         POS_X=+00000 (+00000 .. +06400)
   POS_Y=+00000 (+00000 .. +04800)      PRESSURE=+00000 (+00000 .. +00255)

    LEFT=             MIDDLE=              RIGHT=              EXTRA=
    SIDE=              TOUCH=             STYLUS=            STYLUS2=

Notice that this tablet has no tilt, and the pressure range is considerably reduced. This version of wacdump does not distinguish between tablets with mice, so the left, right, and middle buttons are present, even though the tablet itself has no mouse.






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