Bug#514464: caps lock led does not show up

[Samuel Thibault <sthibault@debian.org>]

Hello,

The patch got into Linus' tree, so it will most probably get into Linux
4.2.  We should thus probably work on the console-setup support for it
already, it won't hurt.

So the idea is that console-setup can configure which modifier lights
which LED, by first emitting udev rules such as this:

ACTION=="add", SUBSYSTEM=="leds", ENV{DEVPATH}=="*/input*::capslock", ATTR{trigger}="kbd-ctrlllock"

for the subsequently-plugged keyboards, and then do the echo by hand for
existing keyboards, similarly to this:

for i in /sys/class/leds/input*::capslock/trigger 
do
	echo kbd-ctrlllock > $i
done

The physical LED names (capslock in the example above) are:

numlock (defaults to kbd-numlock)
capslock (defaults to kbd-capslock)
scrolllock (defaults to kbd-scrolllock)
compose
kana (defaults to kbd-kanalock)
sleep
suspend
mute
misc
mail
charging

and the trigger names (kbd-ctrlllock in the example above) are:

(the 4 legacy LED states)
kbd-scrollock
kbd-numlock
kbd-capslock
kbd-kanalock

(the 8 layout modifiers)
kbd-shiftlock
kbd-altgrlock
kbd-ctrllock
kbd-altlock
kbd-shiftllock
kbd-shiftrlock
kbd-ctrlllock
kbd-ctrlrlock

Anton, do you have all the informations you need to match that with the
xkb data?

Samuel