1What: /sys/class/backlight/<backlight>/bl_power 2Date: April 2005 3KernelVersion: 2.6.12 4Contact: Richard Purdie <rpurdie@rpsys.net> 5Description: 6 Control BACKLIGHT power, values are FB_BLANK_* from fb.h 7 8 - FB_BLANK_UNBLANK (0) : power on. 9 - FB_BLANK_POWERDOWN (4) : power off 10Users: HAL 11 12What: /sys/class/backlight/<backlight>/brightness 13Date: April 2005 14KernelVersion: 2.6.12 15Contact: Richard Purdie <rpurdie@rpsys.net> 16Description: 17 Control the brightness for this <backlight>. Values 18 are between 0 and max_brightness. This file will also 19 show the brightness level stored in the driver, which 20 may not be the actual brightness (see actual_brightness). 21Users: HAL 22 23What: /sys/class/backlight/<backlight>/actual_brightness 24Date: March 2006 25KernelVersion: 2.6.17 26Contact: Richard Purdie <rpurdie@rpsys.net> 27Description: 28 Show the actual brightness by querying the hardware. 29Users: HAL 30 31What: /sys/class/backlight/<backlight>/max_brightness 32Date: April 2005 33KernelVersion: 2.6.12 34Contact: Richard Purdie <rpurdie@rpsys.net> 35Description: 36 Maximum brightness for <backlight>. 37Users: HAL 38 39What: /sys/class/backlight/<backlight>/type 40Date: September 2010 41KernelVersion: 2.6.37 42Contact: Matthew Garrett <mjg@redhat.com> 43Description: 44 The type of interface controlled by <backlight>. 45 "firmware": The driver uses a standard firmware interface 46 "platform": The driver uses a platform-specific interface 47 "raw": The driver controls hardware registers directly 48 49 In the general case, when multiple backlight 50 interfaces are available for a single device, firmware 51 control should be preferred to platform control should 52 be preferred to raw control. Using a firmware 53 interface reduces the probability of confusion with 54 the hardware and the OS independently updating the 55 backlight state. Platform interfaces are mostly a 56 holdover from pre-standardisation of firmware 57 interfaces. 58