The present invention relates to a backlight and ambient light sensor system, and discloses apparatuses and methods to operate a display device of an electronic device. In some embodiments, a method includes receiving a user setting or input of a display control parameter, and causing or altering, based on the user setting or input, an effect of an ambient light sensor value (ALS) on control of the display control parameter. The user input may be an unlock of a touch screen input capability of the display device, and a wake of the display device from an inactivity dim. Also, according to embodiments of the inventions, a method of operating a display of an electronic device includes receiving a change to one of a display brightness output level and an ambient light sensor output level, and altering, according to the change, a display brightness or contrast output level. Other apparatuses and methods and data processing systems and machine readable media are also described.