I'm using i.MX6 sabresd for my board and ubuntu 16.04 for my os system.
When I go into the sleeping mode I will run `echo mem > /sys/power/state `.
And the back light will turn off.
Here I got some questions:
1. Where will it turned off the back light when I run `echo mem > /sys/power/state ` and how do it know which back light pin I've defined.
2. Which device will it turned off ?
Any answers or documents can provide me to understand it?
Thanks in Advanced!