sysfs-class-backlight 1.9 KB

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  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. What: /sys/class/backlight/<backlight>/brightness
  11. Date: April 2005
  12. KernelVersion: 2.6.12
  13. Contact: Richard Purdie <rpurdie@rpsys.net>
  14. Description:
  15. Control the brightness for this <backlight>. Values
  16. are between 0 and max_brightness. This file will also
  17. show the brightness level stored in the driver, which
  18. may not be the actual brightness (see actual_brightness).
  19. Users: HAL
  20. What: /sys/class/backlight/<backlight>/actual_brightness
  21. Date: March 2006
  22. KernelVersion: 2.6.17
  23. Contact: Richard Purdie <rpurdie@rpsys.net>
  24. Description:
  25. Show the actual brightness by querying the hardware.
  26. Users: HAL
  27. What: /sys/class/backlight/<backlight>/max_brightness
  28. Date: April 2005
  29. KernelVersion: 2.6.12
  30. Contact: Richard Purdie <rpurdie@rpsys.net>
  31. Description:
  32. Maximum brightness for <backlight>.
  33. Users: HAL
  34. What: /sys/class/backlight/<backlight>/type
  35. Date: September 2010
  36. KernelVersion: 2.6.37
  37. Contact: Matthew Garrett <mjg@redhat.com>
  38. Description:
  39. The type of interface controlled by <backlight>.
  40. "firmware": The driver uses a standard firmware interface
  41. "platform": The driver uses a platform-specific interface
  42. "raw": The driver controls hardware registers directly
  43. In the general case, when multiple backlight
  44. interfaces are available for a single device, firmware
  45. control should be preferred to platform control should
  46. be preferred to raw control. Using a firmware
  47. interface reduces the probability of confusion with
  48. the hardware and the OS independently updating the
  49. backlight state. Platform interfaces are mostly a
  50. holdover from pre-standardisation of firmware
  51. interfaces.