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