| 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. |