/dev/input/event

The next frustrating event was trying to determine whether the wacom.ko module actually detects the Wacom Graphire2 and then controls it. Here is my `tail -f /var/log/messages' report when the Graphire is first unplugged, the plugged back into, the USB port...

Jul 28 11:43:36 linux kernel: usb 3-2: USB disconnect, address 2 

Jul 28 11:43:36 linux /etc/hotplug/usb.agent[13122]: need a device for this command 

Jul 28 11:43:49 linux kernel: usb 3-2: new low speed USB device using address 3 

Jul 28 11:43:50 linux kernel: usb 3-2: Product: ET-0405A-UV2.0-3 Jul 28 11:43:50 linux kernel: usb 3-2: Manufacturer: WACOM Jul 28 11:43:50 linux kernel: hid: probe of 3-2:1.0 failed with error -5 

Jul 28 11:43:50 linux kernel: evdev: reusing event3 for vendor/product 0x56a/0x11 

Jul 28 11:43:50 linux kernel: input: Wacom Graphire2 4x5 on usb-0000:00:11.2-2 

Jul 28 11:43:50 linux /etc/hotplug/usb.agent[13172]: need a device for this command

Intimidating stuff! The confusing part of this report is that both /etc/hotplug/usb.agent and hid (USB Human Interface Device) seem to report that the device has not been recognised. In fact, we do not want hid to recognise the device, as apparantly hid will treat the Graphire2 as a relative mouse. I think the `good sign' is that `input' recognised the device. I also notice that `evdev' has recognised the device, though I do not recall seeing that message during testing! I actually added the following line to /etc/hotplug/usb.handmap...

wacom 0x0003 0x056a 0x0011 0x0000 0x0000 0x00 0x00 0x00 0x00 0x00 0x00 0x00000000

...but I don't think that made any difference.

The next problem is where are the Graphire2's USB messages being sent to? The LinuxWacom documentation suggests that /dev/input/event? (where ? is a number) is the place to look. In my instance, the correct location is /dev/input/event3 (reference is made to event3 in the /var/log/message quoted above). I confirmed this by using the command `xxd /dev/input/event3', and then watching all the numbers generated when I tapped on the graphics tablet. It is also possible to use `wacdump /dev/input/event3'. `wacdump' is provided in the LinuxWacom package. It has also been pre-compiled into an RPM by one of the SuSE people.