Logitech Trackman in Linux

A simple post on how to configure a Logitech Trackman Marble on GNU/Linux. This post is tested on Ubuntu but since this is Xorg configuration it should be usable almost everywhere.

Out of the box

In Ubuntu, the trackball works out of the box. But I want to configure it to my tastes.

What it is actually missing is the scrolling function. Which is fairly useful while browsing websites and reading pdfs.

What am I looking for

• Faster mouse speed
• Hold Back button + wheel => Scroll
• Simple Back button => Back
• Middle button with 2 button click

xinput and evdev

Evdev is a generic input driver. Most mouses/keyboards can be accesses through it.

xinput is a command line utility to configure X devices. To test options and changes is quite useful and easy to use. With it we can mingle in the settings and test it “live” until getting the desired behaviour.

Button Map

To map the buttons, first we have to know the values of those buttons. For that I used the xev utility. Start xev, mouse-over the small window that appears and press all the buttons like a monkey until you are satisfied. xev will log the values of those presses. When finished, you’ll know which button is which code.

Set Up from command line

List available options

Xinput has a simple option list-props to list all the properties that can be set for a specific device. I won’t drop them all here, but know that you can have a look with:

xinput list-props "Logitech USB Trackball"

Wheel emulation

This is something directly supported by evdev. Enable the “Evdev Wheel Emulation” option:

xinput set-int-prop "Logitech USB Trackball" "Evdev Wheel Emulation Button" 8 8

xinput set-int-prop "Logitech USB Trackball" "Evdev Wheel Emulation" 8 1

The first command will set the wheel emulation to Button 8. (the first 8 is just the integer type), the second command enables the option (set to 1). By default there’s a timeout on emulation activations, so simply clicking the back button will perform the default function (go back).

To scroll you hold the small button down and move the ball up and down, left and right.

Back button

As stated, this just works, so no need to change anything.

Middle button

There’s no middle button in this trackball, and there’s two ways around it. The first one: a classic middle button emulation pressing two buttons, that would be the two big ones (1,3); the second option is to change the behaviour of button 9. Back and forward buttons may seem like a good idea, but they have mostly no use for me.

Enabling the button emulation is straightforward:

xinput set-int-prop "Logitech USB Trackball" "Evdev Middle Button Emulation" 8 1

Remapping is very easy to, but we have to know about the button maps. For that, check the Button Labels line from xinput list:

xinput list-props "Logitech USB Trackball"

Once we know that, use xinput set-button-map with a list of numbers to set a button to each label. The default button configuration is: 1 2 3 4 …, that matches with the functionalities that we have for those buttons out of the box:

• 1) “Button Left”
• 2) There’s no 2 button “Button Middle”
• 3) “Button Right”
• 4) There’s no 4 button “Button Wheel up”
• 5) There’s no 5 button “Button Wheel down”
• 6) There’s no 6 button “Button Horiz Wheel left”
• 7) There’s no 7 button “Button Horiz Wheel right”
• 8) “Button Side”
• 9) “Button Extra”

For our new map, 9 should be “Button Middle”

xinput set-button-map "Logitech USB Trackball" 1 9 3 4 5 6 7 8 2

Mouse speed

By now you have the gist for it. Adjust the Deceleration to your needs.

xinput set-prop "Logitech USB Trackball" "Device Accel Constant Deceleration" 0.7

Auto configuring on X11 start

Now we have a set of commands to set our Trackman as we like. But there’s a problem, I don’t want to type all of this every time my system starts. Realistically it’s not that bad since my laptop usually goes from ON to SLEEP :-D. Anyway, an easy way out is to write all those commands into a shell script, make it executable and run in whenever you plug the Trackman.

But you don’t want that do you? What we’ll do is create an InputDevice. In my case device configurations can be found under /usr/share/X11/xorg.conf.d/. It has some funny files like 51-synaptics-quirks.conf.

Create your own file there: 70-logitech-trackman.conf and fill it with the appropriate options. Mind you that the naming of the options is not exactly the same that we used on the command line with xinput. To know the exact names check the man page of evdev.

#
# InputClass configuration for Logitech USB trackball
#
Section "InputClass"
   Identifier       "TrackmanConfiguration"
   MatchProduct     "Logitech USB Trackball"
   Driver           "evdev"
   Option           "ButtonMapping" "1 9 3 4 5 6 7 8 2"
   Option           "ConstantDeceleration" "0.7"
   Option           "EmulateWheel" "1"
   Option           "EmulateWheelButton" "8"
EndSection

Word of advice (for those not so used to tampering with X11), changing this values to something not valid will prevent X11 from starting. So if after changing it your system does not boot check whatever you wrote for your InputClass.

Extras for lefties

---

..
NOTE from the future:
Michael was kind enough to add a left-handed setup in the comments. Enjoy!
..

---

Section “InputClass”
    Identifier “TrackmanConfiguration”
    MatchProduct “Logitech USB Trackball”
    Driver “evdev”
    Option “ButtonMapping” “3 8 1 4 5 6 7 2 9”
    Option “ConstantDeceleration” “0.7”
    Option “EmulateWheel” “1”
    Option “EmulateWheelButton” “9”
EndSection

Conclusions

And that’s it. Now I can plug/unplug my trackball as I see fit. And when I forget how I configured it this blog page will exist 😛

References

EVDEV man page ⇒GO
XEV man page ⇒GO
xinput man page⇒GO
Logitech Trackman⇒GO
Xorg page on InputDevice ⇒GO