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 compatible with
  7. FB_BLANK_* from fb.h
  8. - 0 (FB_BLANK_UNBLANK) : power on.
  9. - 4 (FB_BLANK_POWERDOWN) : power off
  10. Users: HAL
  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. What: /sys/class/backlight/<backlight>/actual_brightness
  22. Date: March 2006
  23. KernelVersion: 2.6.17
  24. Contact: Richard Purdie <rpurdie@rpsys.net>
  25. Description:
  26. Show the actual brightness by querying the hardware.
  27. Users: HAL
  28. What: /sys/class/backlight/<backlight>/max_brightness
  29. Date: April 2005
  30. KernelVersion: 2.6.12
  31. Contact: Richard Purdie <rpurdie@rpsys.net>
  32. Description:
  33. Maximum brightness for <backlight>.
  34. Users: HAL
  35. What: /sys/class/backlight/<backlight>/type
  36. Date: September 2010
  37. KernelVersion: 2.6.37
  38. Contact: Matthew Garrett <mjg@redhat.com>
  39. Description:
  40. The type of interface controlled by <backlight>.
  41. "firmware": The driver uses a standard firmware interface
  42. "platform": The driver uses a platform-specific interface
  43. "raw": The driver controls hardware registers directly
  44. In the general case, when multiple backlight
  45. interfaces are available for a single device, firmware
  46. control should be preferred to platform control should
  47. be preferred to raw control. Using a firmware
  48. interface reduces the probability of confusion with
  49. the hardware and the OS independently updating the
  50. backlight state. Platform interfaces are mostly a
  51. holdover from pre-standardisation of firmware
  52. interfaces.