Can't disable backlit keyboard on Sony Viao, Ubuntu 13.04, 64bit

Question

I need to turn off the backlit keyboard on my Sony Viao, with 64 bit Ubuntu 13.04. I'm prone to migraines, and the lights really bother my eyes.

I've tried several posted solutions, none work. (although one worked on Ubuntu 12.xx 32bit)

Here are some of the threads I've tried:

• Keyboard backlighting not working on a Vaio VPCSB11FX
• Cant disable, control keyboard backlight on sony vaio vpcf236fm
• keyboard backlit - Ubuntu 12.10 - Sony Vaio
• Keyboard backlighting not working on a Vaio VPCSB11FX

These don't work:

echo 0 > /sys/devices/platform/sony-laptop/kbd_backlight

     the directory exists, but not the file.

This looked promising:

sudo modprobe -v sony-laptop
modinfo sony-laptop

But then, neither of these worked:

sudo modprobe -v sony-laptop kbd_backlight=0
sudo rmmod -v sony-laptop; sudo modprobe -v sony-laptop kbd_backlight=0

I guess I'll try this anyway, and reboot:

echo "options sony-laptop kbd_backlight=0" | sudo tee /etc/modprobe.d/sony-laptop.conf

I'll let you know if it worked.