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