Re: [DIGImend-users] Huion 610p tablet and hardware buttons

[Christopher B. <chr...@gm...>]

On Wed, 25 Mar 2015 15:13:08 +0100
co...@pi... wrote:

>Dear Alec,
>
>Some times ago, I had a discussion with someone on how to map the
>button of the tablet, here is the solution we came up with :
>
>(a little disclaimer: I am not exactly a computer scientist and I have 
>managed to make the key "work" but it is not really clean and I won't
>be able to explain every step in depth ^^.
>A documentation that has helped me a lot is available on the arch
>wiki : https://wiki.archlinux.org/index.php/Map_scancodes_to_keycodes)
>
>Anyway, here is the full process I have followed :
>1. First, you need to identify the vendor_id and product_id of your 
>tablet by looking for it in the usb device list (with the 'lsusb' 
>command), my vendor ID is 256C and my product ID is 006E. I guess they 
>are the same for you but you may want to check.
>2. Then, you can create the .hwdb file containing your rules in 
>/etc/udev/hwdb.d
>I have called mine huion.hwdb
>Before writing the rules for the tablet, you need to specify that
>those rules will apply to this device by specifying its ID as :
>keyboard:usb:v256Cp006E*
>  KEYBOARD_KEY_700e0=unknown # This is a rule, see below
>
>After the first line, each rule line begins with a space. A rule is 
>defined on the left of the equality by the input key and on the right
>by the new key you want to have.
>3. To identify scancodes, I have used the command 'evtest' in root. It 
>asks you to choose the right device, for some reasons I had several 
>huion tablet listed, so I tried them all and used the one that
>actually responded to the input buttons.
>You can find in the attached file the output I get when I press the 
>eraser button.
>The first 5 lines seem to be triggered by the push down of the button 
>and the last 5 ones by the release.
>
>The first line say that the first key to be pressed has the code 700e1 
>and the following line tells us that it is LEFT_SHIFT.
>Then the two following lines say that the key KPMINUS is pressed and
>its code is 70056
>Hence, by default, pressing the eraser button leads to "shift"+ "-" 
>which is not exactly what I want. And by testing the other buttons you 
>will see that each one uses some key modifier like Alt or Ctrl.
>
>4. Now that you have identified the inputs associated to this button, 
>you can remap it in your .hwdb file
>--> From this point I have made very personal choices that you may
>want to change ^^
>I have decided to get rid of the modifier keys "shift", "alt" and
>"ctrl" so I have first mapped them to the key "rightctrl" (I did not
>find a way to completely discard these inputs), and then I have
>assigned the other inputs to key that are not on my keyboard : f13->f21
>
>Here is my .hwdb file :
>
>keyboard:usb:v256Cp006E*
>  KEYBOARD_KEY_700e0=rightctrl # map ctrl to something useless like 
>rightctrl
>  KEYBOARD_KEY_700e1=rightctrl # shift -> rightctrl
>  KEYBOARD_KEY_700e2=rightctrl # alt -> rightctrl
>  KEYBOARD_KEY_7003d=f13 # back button -> f13
>  KEYBOARD_KEY_70016=f14 # eraser --> f14
>  KEYBOARD_KEY_70056=f15 # pencil --> f15
>  KEYBOARD_KEY_70057=f16 # + --> f16
>  KEYBOARD_KEY_7000a=f17 # - -->f17
>  KEYBOARD_KEY_70019=f18 # pencil + --> f18
>  KEYBOARD_KEY_7001b=f21 # pencil - --> f21
>  KEYBOARD_KEY_70006=f20 # hand --> f20
>
>I have assigned the inputs to keys that are not on my keyboard to be 
>able to use the same button for different shortcut depending on the
>used application by using "autokey" which enables to remap (again...)
>keys to others depending on the current application.
>
>(For autokey, see for instance 
>http://www.howtogeek.com/howto/26913/how-to-customize-shortcut-keys-for-any-linux-application/ 
>)
>
>5. to load the rules you must do (as root) :
>
>udevadm hwdb --update
>udevadm trigger
>
>6. You can check your rules by launching evtest again.
>
>I think that there is a cleaner way to proceed, especially concerning 
>the modifier keys, but it seems to work...
>I hope this helps!
>
>

Nice and concise writeup - thanks a lot! You should write manuals
for a living :)

--
Regards,
Christopher Barry

Random geeky fortune:
The human race has one really effective weapon, and that is laughter.
		-- Mark Twain