Apply udev rule on reboot if device is present

exebook

11/23/23, 8:37 AM

This code must be executed each time my Keychron K1 keyboard is about to be used:

echo 2 > /sys/module/hid_apple/parameters/fnmode

The code enables Fn keys as the Keychron suggests on Linux.

I put it in a script /home/me/k1add

After hours of desperation I successfully wrote this rule:

SUBSYSTEM=="hid", ENV{HID_PHYS}=="*input0", ACTION=="add",
ATTRS{idVendor}=="05ac", ATTRS{idProduct}=="024f", RUN="/home/me/k1add"

(I wrapped the rule text here for your convenient reading).

The rule goes to:

/etc/udev/rules.d/10-my.rules

Now if I unplug and plug back the keyboard the rule applies and I am happy. But after I restart the PC nothing happens. So what is the way here to make it run on reboot? I know I can add this code to some of the rc scripts, but then this code would execute even if I use another keyboard, which might not be a big problem but anyway I believe it's udev's work to run a script each time a device is ready.

I guessed there might be another ACTION but man udev does not list possible actions. I know I can see actions with udevadm monitor but this command can only be executed after the system is fully booted, which is too late to detect the udev action.

495

0 + 4

keyboard

usb

udev

matigo

11/23/23, 8:48 AM

Where did you write that rule to? `/etc/udev/rules.d/`? If so, what is the name of the `.rules` file?

exebook

11/23/23, 9:02 AM

@matigo `/etc/udev/rules.d/10-my.rules`

nobody

11/23/23, 9:17 AM

Put the script under /usr/local/bin/ and change the path to it in your udev rule

matigo

11/23/23, 9:48 AM

It may be worthwhile to change the `.rules` file to be prefixed with `99` or another "high" number as there could be some items that need to be handled before the keyboard. The `.rules` files are read in the order they appear in the directory, so items you make are generally best added to the "end" of the directory

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Apply udev rule on reboot if device is present

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