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Diffstat (limited to 'Documentation/ABI/stable')
| -rw-r--r-- | Documentation/ABI/stable/sysfs-class-backlight | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/ABI/stable/sysfs-class-backlight b/Documentation/ABI/stable/sysfs-class-backlight index 4d637e1c4ff7..70302f370e7e 100644 --- a/Documentation/ABI/stable/sysfs-class-backlight +++ b/Documentation/ABI/stable/sysfs-class-backlight @@ -34,3 +34,23 @@ 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. |