Ubuntu – Caps lock indicator not synced

indicatorkeyboard

I have a laptop which I hook up to an external display when I'm at home. I also connected an external keyboard and mouse which makes it more comfortable for me.

I have noticed that pressing caps lock on the external keyboard does not light up the capslock indicator of the laptop keyboard (and vice versa).

When googling, I came across the setleds function, but when I type it into a console all I get is this:

KDGKBLED: Inappropriate ioctl for device
Error reading current flags setting. Maybe you are not on the console?

Any idea if I can get this working?

Best Answer

This is a confirmed bug and there is nothing that you can do for the moment to fix it (I have the same issue):

Also, setleds it's working only in console mode (one among tty1-tty6), but this will not solve the problem. Check man setleds to see what it's purpose is (there is also one example there).

How to use:

Copy the script into an empty file, save it as fix_led (no extension) in /usr/local/bin and make it executable.
Since you need to edit the file /sys/class/leds/input45::capslock/brightness you need to add the script to the sudoers file, as explained e.g. here.
Test- run the script by running
```
sudo /usr/local/bin/fix_led
```
in a terminal, test your Caps Lock key.
Now add the script to your startup applications: Dash > Startup Applications > Add. Add the command:
```
/bin/bash -c "sleep 10 && sudo /usr/local/bin/fix_led"
```

That's it. On next restart (log in), it should work.

Notes

Of course, the patch should work in all situations where the led is not functioning. the exact location of the file capslock/brightness may vary however. Set, if necessary, the location in the line:
```
led = "/sys/class/leds/input45::capslock/brightness"
```
in the head of the script (don't escape the : in python). I tested the script by making it set the led the wrong way :) (led off when Caps Lock was on, on when it was off).
The extra load of the script is none.

Explanation

Information on the current Caps Lock state can be fetched by the command:

xset -q

Once per second, the script checks if Caps Lock: on is in the output. The script also checks if the current state matches the led state (either 1 or 0), as read from the capslock/brightness file.

If these two do not match, the script sets the led state according to the real Caps Lock state.

Ubuntu – Manage Keyboard backlight on dual boot system

Keyboard backlight

Any vendor

From Arch Linux wiki: You can control your computer keyboard backlight via the D-Bus interface. The benefits of using it are that no modification to device files is required and it is vendor agnostic.

Here is an example implementation in Python 3. Place the following script in /usr/local/bin/ and make it executable. You can then map your keyboard shortcuts to run /usr/local/bin/kb-light.py + and /usr/local/bin/kb-light.py - to increase and decrease your keyboard backlight level.

Here is python code for /usr/local/bin/kb-light.py:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-    
from sys import argv
import dbus


def kb_light_set(delta):
    bus = dbus.SystemBus()
    kbd_backlight_proxy = bus.get_object('org.freedesktop.UPower', '/org/freedesktop/UPower/KbdBacklight')
    kbd_backlight = dbus.Interface(kbd_backlight_proxy, 'org.freedesktop.UPower.KbdBacklight')

    current = kbd_backlight.GetBrightness()
    maximum = kbd_backlight.GetMaxBrightness()
    new = max(0, current + delta)

    if new >= 0 and new <= maximum:
        current = new
        kbd_backlight.SetBrightness(current)

    # Return current backlight level percentage
    return 100 * current / maximum

if __name__ == '__main__':
    if len(argv[1:]) == 1:
        if argv[1] == "--up" or argv[1] == "+":
            # ./kb-light.py (+|--up) to increment
            print(kb_light_set(1))
        elif argv[1] == "--down" or argv[1] == "-":
            # ./kb-light.py (-|--down) to decrement
            print(kb_light_set(-1))
        else:
            print("Unknown argument:", argv[1])
    else:
        print("Script takes exactly one argument.", len(argv[1:]), "arguments provided.")