Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / ABI / stable / sysfs-class-backlight

diff --git a/kernel/Documentation/ABI/stable/sysfs-class-backlight b/kernel/Documentation/ABI/stable/sysfs-class-backlight
new file mode 100644 (file)
index 0000000..70302f3
--- /dev/null
+++ b/kernel/Documentation/ABI/stable/sysfs-class-backlight
@@ -0,0 +1,56 @@
+What:          /sys/class/backlight/<backlight>/bl_power
+Date:          April 2005
+KernelVersion: 2.6.12
+Contact:       Richard Purdie <rpurdie@rpsys.net>
+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/<backlight>/brightness
+Date:          April 2005
+KernelVersion: 2.6.12
+Contact:       Richard Purdie <rpurdie@rpsys.net>
+Description:
+               Control the brightness for this <backlight>. 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/<backlight>/actual_brightness
+Date:          March 2006
+KernelVersion: 2.6.17
+Contact:       Richard Purdie <rpurdie@rpsys.net>
+Description:
+               Show the actual brightness by querying the hardware.
+Users:         HAL
+
+What:          /sys/class/backlight/<backlight>/max_brightness
+Date:          April 2005
+KernelVersion: 2.6.12
+Contact:       Richard Purdie <rpurdie@rpsys.net>
+Description:
+               Maximum brightness for <backlight>.
+Users:         HAL
+
+What:          /sys/class/backlight/<backlight>/type
+Date:          September 2010
+KernelVersion: 2.6.37
+Contact:       Matthew Garrett <mjg@redhat.com>
+Description:
+               The type of interface controlled by <backlight>.
+               "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.