| Corentin Chary | 3c4c1b6 | 2009-08-28 12:56:43 +0000 | [diff] [blame] | 1 | What: /sys/class/backlight/<backlight>/bl_power |
| 2 | Date: April 2005 |
| 3 | KernelVersion: 2.6.12 |
| 4 | Contact: Richard Purdie <rpurdie@rpsys.net> |
| 5 | Description: |
| 6 | Control BACKLIGHT power, values are FB_BLANK_* from fb.h |
| 7 | - FB_BLANK_UNBLANK (0) : power on. |
| 8 | - FB_BLANK_POWERDOWN (4) : power off |
| 9 | Users: HAL |
| 10 | |
| 11 | What: /sys/class/backlight/<backlight>/brightness |
| 12 | Date: April 2005 |
| 13 | KernelVersion: 2.6.12 |
| 14 | Contact: Richard Purdie <rpurdie@rpsys.net> |
| 15 | Description: |
| 16 | Control the brightness for this <backlight>. Values |
| 17 | are between 0 and max_brightness. This file will also |
| 18 | show the brightness level stored in the driver, which |
| 19 | may not be the actual brightness (see actual_brightness). |
| 20 | Users: HAL |
| 21 | |
| 22 | What: /sys/class/backlight/<backlight>/actual_brightness |
| 23 | Date: March 2006 |
| 24 | KernelVersion: 2.6.17 |
| 25 | Contact: Richard Purdie <rpurdie@rpsys.net> |
| 26 | Description: |
| 27 | Show the actual brightness by querying the hardware. |
| 28 | Users: HAL |
| 29 | |
| 30 | What: /sys/class/backlight/<backlight>/max_brightness |
| 31 | Date: April 2005 |
| 32 | KernelVersion: 2.6.12 |
| 33 | Contact: Richard Purdie <rpurdie@rpsys.net> |
| 34 | Description: |
| 35 | Maximum brightness for <backlight>. |
| 36 | Users: HAL |
| Matthew Garrett | bb7ca74 | 2011-03-22 16:30:21 -0700 | [diff] [blame] | 37 | |
| 38 | What: /sys/class/backlight/<backlight>/type |
| 39 | Date: September 2010 |
| 40 | KernelVersion: 2.6.37 |
| 41 | Contact: Matthew Garrett <mjg@redhat.com> |
| 42 | Description: |
| 43 | The type of interface controlled by <backlight>. |
| 44 | "firmware": The driver uses a standard firmware interface |
| 45 | "platform": The driver uses a platform-specific interface |
| 46 | "raw": The driver controls hardware registers directly |
| 47 | |
| 48 | In the general case, when multiple backlight |
| 49 | interfaces are available for a single device, firmware |
| 50 | control should be preferred to platform control should |
| 51 | be preferred to raw control. Using a firmware |
| 52 | interface reduces the probability of confusion with |
| 53 | the hardware and the OS independently updating the |
| 54 | backlight state. Platform interfaces are mostly a |
| 55 | holdover from pre-standardisation of firmware |
| 56 | interfaces. |