From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/ABI/stable/sysfs-class-backlight | 56 ++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 Documentation/ABI/stable/sysfs-class-backlight (limited to 'Documentation/ABI/stable/sysfs-class-backlight') diff --git a/Documentation/ABI/stable/sysfs-class-backlight b/Documentation/ABI/stable/sysfs-class-backlight new file mode 100644 index 00000000..70302f37 --- /dev/null +++ b/Documentation/ABI/stable/sysfs-class-backlight @@ -0,0 +1,56 @@ +What: /sys/class/backlight//bl_power +Date: April 2005 +KernelVersion: 2.6.12 +Contact: Richard Purdie +Description: + Control BACKLIGHT power, values are FB_BLANK_* from fb.h + - FB_BLANK_UNBLANK (0) : power on. + - FB_BLANK_POWERDOWN (4) : power off +Users: HAL + +What: /sys/class/backlight//brightness +Date: April 2005 +KernelVersion: 2.6.12 +Contact: Richard Purdie +Description: + Control the brightness for this . Values + are between 0 and max_brightness. This file will also + show the brightness level stored in the driver, which + may not be the actual brightness (see actual_brightness). +Users: HAL + +What: /sys/class/backlight//actual_brightness +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie +Description: + Show the actual brightness by querying the hardware. +Users: HAL + +What: /sys/class/backlight//max_brightness +Date: April 2005 +KernelVersion: 2.6.12 +Contact: Richard Purdie +Description: + Maximum brightness for . +Users: HAL + +What: /sys/class/backlight//type +Date: September 2010 +KernelVersion: 2.6.37 +Contact: Matthew Garrett +Description: + The type of interface controlled by . + "firmware": The driver uses a standard firmware interface + "platform": The driver uses a platform-specific interface + "raw": The driver controls hardware registers directly + + In the general case, when multiple backlight + interfaces are available for a single device, firmware + control should be preferred to platform control should + be preferred to raw control. Using a firmware + interface reduces the probability of confusion with + the hardware and the OS independently updating the + backlight state. Platform interfaces are mostly a + holdover from pre-standardisation of firmware + interfaces. -- cgit v1.2.3