I am trying to force the capslock led on. xset does not work for me, so I am trying to use setleds.

In a graphical console, this command returns:

> LANG=C setleds -L +caps
KDGKBLED: Inappropriate ioctl for device
Error reading current flags setting. Maybe you are not on the console?

In a virtual terminal, it works, however the effect is local to that virtual terminal. From what I understand, running

> setleds -L +caps < /dev/tty1

from a virtual terminal (my X server is sitting on tty1) should work. However, this requires root access.

Is there a way to send a command to the console underlying a X server, be it from the said xserver or from another VT, without root?

Edit: From a suggestion from Mark Plotnik, and based on code found here, I wrote and compiled the following:

#include <X11/Xlib.h>
#include <X11/XKBlib.h>

#define SCROLLLOCK 1
#define CAPSLOCK 2
#define NUMLOCK 16

void setLeds(int leds) NUMLOCK,
 leds & (CAPSLOCK 

int main() 
 setLeds(CAPSLOCK);
 return 0;

From what Gilles wrote about xset, I did not expect it to work, but it does... in some sense: it sets the led, but it also sets the capslock status. I do not fully understand all the code above, so I may have done a silly mistake. Apparently, the line XChangeKeyboardControl... does not change the behavior of the program, and XkbLockModifiers is what sets the led and the capslock status.

In principle, you should be able to do it with the venerable xset command.

xset led named 'Caps Lock'

or xset led 4 to set LED number 4, if your system doesn't recognize the LEDs by name.

However, this doesn't seem to work reliably. On my machine, I can only set Scroll Lock this way, and I'm not the only one. This seems to be a matter of XKB configuration.

The following user-level work-around should work (for the most part):

1. 
   

   Extract your current xkb configuration:

   
   
   

   xkbcomp $DISPLAY myconf.xkb
   

   
   


2. 
   

   Edit the file myconf.xkb, replacing !allowExplicit with allowExplicit in the relevant blocks:

   
   
   

   indicator "Caps Lock" 
    allowExplicit;
    whichModState= locked;
    modifiers= Lock;
   ;
   indicator "Num Lock" 
    allowExplicit;
    whichModState= locked;
    modifiers= NumLock;
   ;
   

   
   


3. 
   

   Load the new file

   
   
   

   xkbcomp myconf.xkb $DISPLAY
   

   
   

Now setting the leds on and off with xset should work. According to the bug report, you will not be able to switch the leds off when they are supposed to be on (for example if CapsLock is enabled).

Using sed

$ sudo sed -i 's|!allowExplicit|allowExplicit|g' /usr/share/X11/xkb/compat/ledcaps

After logging out and in again, the Caps Lock LED can now be controlled without any root privileges using the commands:

$ xset led named 'Caps Lock'
$ xset -led named 'Caps Lock'