"Keyboard Backlight not working."に関する回答If you’ve turned off your touch pad using fn-f9, then use fn-f9 to toggle it back on momentarily. Then, while the touchpad is momentarily active, try fn-f4 to brighten and fn-f3 to dim the backlight to desired level. Once at the desired level you may opt to disable the touchpad again using fn-f9. Bright and dim will continue to function as expected going forward until the next time your computer sleeps or re-boots. Should bright and dim stop responding, simply repeat the fn-f9 toggle trick and you should be all set.