After reading dozens of other posts and nothing seems to work, I've located "keyboard backlight" in the /sys/module/sony_laptop/parameters/ module but don't know how to get it to switch on.
I've downloaded the Sony VAIO control center for Linux here but don't know how to use it to enable the keyboard backlight. Can anyone help with that please?
I feel so close yet so far away. I've been trying to solve this problem for many days and hours so any help would be much appreciated.
I found it. Open nautilus first with
sudo nautilus
Navigate to
/sys/devices/platform/sony-laptop
There is a file called kbd_backlight
Open it, there should be a 0 or a -1. Edit it to just leave a 1.
Done. I replace for a 0 and save, backlight instantly turns off, change again to 1 and instantly on. No reboot needed.
Hope it helps.
a simpler way to do NotNamed420's solution in a single line would be to run:
echo 1 | sudo tee /sys/devices/platform/sony-laptop/kbd_backlight
