可以通过echo(写)和cat(读)来设置背光亮度
E:\adbTools>adb shell
MeizuM8cLite:/ # cd sys/class/leds
MeizuM8cLite:/sys/class/leds # ls
blue green lcd-backlight mmc0:: mmc1:: mx-led
MeizuM8cLite:/sys/class/leds # cd lcd-backlight/
MeizuM8cLite:/sys/class/leds/lcd-backlight # ls
brightness device max_brightness power subsystem trigger uevent
MeizuM8cLite:/sys/class/leds/lcd-backlight # echo 255 > brightness
MeizuM8cLite:/sys/class/leds/lcd-backlight # echo 100 >brightness
MeizuM8cLite:/sys/class/leds/lcd-backlight # cat brightness
100
