add dbrightness attribute for leds, overriding brightness.
[kernel-power] / kernel-power-settings / config /
drwxr-xr-x   ..
-rw-r--r-- 245 default
-rw-r--r-- 243 ideal
-rw-r--r-- 245 lv
-rw-r--r-- 245 ulv
-rw-r--r-- 245 xlv