k810_k811_fkeys

Logitech K810/K811 Keyboard F-keys switcher for Linux (Ubuntu)

Usage

sudo k81x-fkeys [-d device_path] [-v] on|off

"On" enables the regular functions of F1-F13 keys and special functions (like volume or brightness) are accessible after pressing the Fn key. "Off" does the opposite.

Binary installation

If your system supports deb files, you can simply grab an automatic build from https://github.com/themech/k810_k811_fkeys/releases and install it:

sudo dpkg -i k81x-fkeys_<version>_amd64.deb

You can then run the program at /opt/k81x/k81x-fkeys.

For Arch Linux you can use the AUR package:

gpg --recv-keys --keyserver hkp://pool.sks-keyservers.net 7FBFBFD17A45CAE7
pacaur -S k81x-fkeys

Installing from source code

Building

Simply download the source and either run make or compile it yourself by running:

g++ k81x-fkeys.cpp k81x.cpp -o k81x-fkeys -ludev

Installing via make

You can type sudo make install to install the binary and udev the scripts.

Manual installation

I find it convenient to setup an udev rule for this utility so it automatically sets the desired F-keys functions when the keyboard is connecting.

In order to do so copy the k81x-fkeys binary to some location (like /opt/k81x/) and add a following k81x.sh bash script in the same directory:

#!/bin/bash
if [ -z "$1" ];
then
    /opt/k81x/k81x-fkeys -s on
else
    /opt/k81x/k81x-fkeys -s -u $1 on
fi

You can change on to off it that's your desired setup. And specify a device path with -d switch in case the autodetection doesn't work. Also remember about the execute permission: chmod a+x /opt/k81x/k81x.sh.

Now it is time to hook this bash script into udev. Create /etc/udev/rules.d/00-k81x.rules with the following content:

ACTION=="add", KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{address}=="XX:XX:XX:XX:XX:XX", RUN+="/opt/k81x/k81x.sh"

The XX:XX:XX:XX:XX:XX should be replaced with your keyboard Bluetooth address. To find the address simply go to the Bluetooth settings (All Settings>Bluetooth), select the Logitech keyboard on the Devices list and copy its address displayed there. You can also skip the ATTRS{address}=="XX:XX:XX:XX:XX:XX", part. In that case k81x.sh will be also executed for other devices but won't do anything.

Note: On some systems the address attribute is not available. You can try removing it and using this generic rule instead:

ACTION=="add", KERNEL=="hidraw*", SUBSYSTEM=="hidraw", RUN+="/opt/k81x/k81x.sh %S%p"

This means the k81x.sh can also be triggered for other HID devices than you keyboard. But as we're passing the device path as the parameter, calls from those devices will be ignored.