Re: [DIGImend-devel] Genius PenSketch 12x9 in Ubuntu Precise (12.04)

[Nikolai K. <sp...@gm...>]

Hi Viktoria,

On 07/26/2012 08:53 AM, Viktoria S. wrote:
> I have a look at this too. Based on this: http://www.reactivated.net/writing_udev_rules.html#basic
> You can name devices like this too:
> KERNEL=="hdb", NAME="my_spare_disk"

This would name the device node. We need to change the event device name,
which is retrieved with EVIOCGNAME ioctl.

> But my question is how you want to identify the pen?
> To me there are no diferences from the udev perspective between the mouse
> and the pen.

Take a look at the output of "sudo udevadm monitor --property" while
plugging-in the tablet.

Here is an excerpt from the output for Waltop Media Tablet 10.6" pen:

KERNEL[519.062576] add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1:1.0/input/input18 (input)
ABS=1000003
ACTION=add
DEVPATH=/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1:1.0/input/input18
EV=1b
KEY=1c01 0 0 0 0 0 0 0 0 0 0
MODALIAS=input:b0003v172Fp0501e0110-e0,1,3,4,k140,14A,14B,14C,ra0,1,18,m4,lsfw
MSC=10
NAME="WALTOP International Corp. Media Tablet"
PHYS="usb-0000:00:1d.0-1/input0"
PRODUCT=3/172f/501/110
PROP=0
SEQNUM=1444
SUBSYSTEM=input
UDEV_LOG=3
UNIQ=""

Evtest outputs this for the corresponding event device:

Input driver version is 1.0.1
Input device ID: bus 0x3 vendor 0x172f product 0x501 version 0x110
Input device name: "WALTOP International Corp. Media Tablet"
Supported events:
   Event type 0 (EV_SYN)
   Event type 1 (EV_KEY)
     Event code 320 (BTN_TOOL_PEN)
     Event code 330 (BTN_TOUCH)
     Event code 331 (BTN_STYLUS)
     Event code 332 (BTN_STYLUS2)
   Event type 3 (EV_ABS)
     Event code 0 (ABS_X)
       Value      0
       Min        0
       Max    18000
       Resolution      78
     Event code 1 (ABS_Y)
       Value      0
       Min        0
       Max    11000
       Resolution      78
     Event code 24 (ABS_PRESSURE)
       Value      0
       Min        0
       Max     1023
   Event type 4 (EV_MSC)
     Event code 4 (MSC_SCAN)

The udev properties include EV, KEY, ABS and MSC - these are values
retrievable with the EVIOCGBIT ioctl (which is what evtest and evdev driver
do). EV is the bitmask of supported event types, which are EV_SYN, EV_KEY,
EV_ABS and EV_MSC. EV_KEY is the bitmask for supported keys, EV_ABS -
absolute axes, EV_MSC - miscellaneous events.

Take a look at "Using the Input Subsystem, Part II" from the Linux Journal:
http://www.linuxjournal.com/node/6429/print, especially "Listing 6. Finding
a Unique Identifier"

My theory is that you can match against these properties in an udev rule.

Sincerely,
Nick