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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
| commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
| tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /Documentation/ABI/stable/sysfs-class-backlight | |
| parent | Initial commit. (diff) | |
| download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip | |
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/ABI/stable/sysfs-class-backlight')
| -rw-r--r-- | Documentation/ABI/stable/sysfs-class-backlight | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/Documentation/ABI/stable/sysfs-class-backlight b/Documentation/ABI/stable/sysfs-class-backlight new file mode 100644 index 000000000..70302f370 --- /dev/null +++ b/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. |