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Linux Wacom Project HOWTO

3.9 - Viewing the Raw Data (xxd)






View the raw data from the tablet, by returning to the /dev/input directory and streaming the data directly from the device. Be patient here because this is where a lot of people are getting stuck.

[root@ayukawa usb]# cd /dev/input
[root@ayukawa input]# xxd event0
0000000: e65d c33d 597d 0100 0100 4101 0100 0000  .].=Y}....A.....
0000010: e65d c33d 5c7d 0100 0400 0000 b701 2800  .].=\}........(.
0000020: e65d c33d d9bb 0100 0100 4101 0000 0000  .].=......A.....
0000030: e65d c33d dcbb 0100 0400 0000 b701 2800  .].=..........(.
(Ctrl-C)

First off, you have to move the mouse or tap the pen to get any output. If the tablet is mapped to event0, a continuously data stream will be displayed while you move the mouse or pen on the tablet. Second, you might not get anything at all. Don't panic. This seems to happen occasionally. If absolutely no output occurs, try event1 and event2. If no output occurs on those ports, reload the drive:

[jej@sasami root]# /sbin/rmmod wacom
[jej@sasami root]# /sbin/modprobe wacom       (or /sbin/insmod mydir/src/wacom.o)
[jej@sasami root]# tail /var/log/messages
Nov 27 17:31:31 sasami kernel: usb.c: deregistering driver wacom
Nov 27 17:31:34 sasami kernel: usb.c: registered new driver wacom
Nov 27 17:31:35 sasami kernel: input0: Wacom Intuos2 12x12 on usb1:2.0
Nov 27 17:31:35 sasami kernel: wacom.c: v1.43-0.9.5 Vojtech Pavlik <vojtech@suse.cz>

The device driver and the tablet occassionally get out of sync with the tablet thinking it's still in HID mode when in fact it should be in "mode 2." By unloading and reloading the driver manually, the initialization code has another opportunity to get it right. Try the xxd /dev/input/event0 again. This time, it should work. If not, send me some email.

Incidentally, if you have a program running that is connected to /dev/input/event0 (like X or wacdump for instance), it is possible that the tablet will not reattach back to the same event. I have seen the wacom reattach to /dev/input/event1 when unloading and reloading the wacom driver with wacdump running for instance. So, try xxd on event1 or event2 if event0 fails.

You should also try running xxd on /dev/input/mouse0. You should get streams of data when the mouse and pen are moved around the surface of the tablet. It is this device that X will look at for mouse movement. Use Ctrl-C to exit xxd.






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