How to swap the "fn" use of Function keys on an Apple Keyboard in Linux

echo 0 > /sys/module/hid_apple/parameters/fnmode

Or, in case of permission issue:

echo 0 | sudo tee /sys/module/hid_apple/parameters/fnmode

This will prevent you from having to reboot. Adding the option is a good idea, so the change persists through reboots.

• 0 = Fn key disabled
• 1 = Fn key pressed by default
• 2 = Fn key released by default

From /drivers/hid/hid-apple.c line 42:

Mode of fn key on Apple keyboards (0 = disabled, [1] = fkeyslast, 2 = fkeysfirst)

The answer above about what option to set in /etc/modprobe.d is a bit out of date. Fortunately there is detailed documentation on the Apple Keyboard support:

1. Edit or create the file /etc/modprobe.d/hid_apple.conf, e.g.:

   gksudo gedit /etc/modprobe.d/hid_apple.conf

2. Add this line to the previously open file.

   options hid_apple fnmode=2

3. Save the file and execute the following command to notify hid_apple module to reload it's configuration.

   sudo update-initramfs -u

4. Reboot

I'd personally recommend sudo update-initramfs -u -k all to update it for all your kernels (once you are confident the setting works as expected).

Setting the fnmode under /sys still works the same way:

sudo -s 'echo 2 > /sys/module/hid_apple/parameters/fnmode'

The values in both methods are as follows:

• 0 = disabled : Disable the 'fn' key. Pressing 'fn'+'F8' will behave like you only press 'F8'
• 1 = fkeyslast : Function keys are used as last key. Pressing 'F8' key will act as a special key. Pressing 'fn'+'F8' will behave like a F8.
• 2 = fkeysfirst : Function keys are used as first key. Pressing 'F8' key will behave like a F8. Pressing 'fn'+'F8' will act as special key (play/pause)

From Here

how do we swap the function of the Fn key?

First edit /etc/modprobe.d/options

sudo nano /etc/modprobe.d/options

and make sure it has the line

options hid pb_fnmode=2

Then save and exit. Lastly, we need to update ramfs:

sudo update-initramfs -u -v -k uname -r

Then just reboot!