13c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/bl_power 23c4c1b69SCorentin CharyDate: April 2005 33c4c1b69SCorentin CharyKernelVersion: 2.6.12 43c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 53c4c1b69SCorentin CharyDescription: 63c4c1b69SCorentin Chary Control BACKLIGHT power, values are FB_BLANK_* from fb.h 73c4c1b69SCorentin Chary - FB_BLANK_UNBLANK (0) : power on. 83c4c1b69SCorentin Chary - FB_BLANK_POWERDOWN (4) : power off 93c4c1b69SCorentin CharyUsers: HAL 103c4c1b69SCorentin Chary 113c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/brightness 123c4c1b69SCorentin CharyDate: April 2005 133c4c1b69SCorentin CharyKernelVersion: 2.6.12 143c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 153c4c1b69SCorentin CharyDescription: 163c4c1b69SCorentin Chary Control the brightness for this <backlight>. Values 173c4c1b69SCorentin Chary are between 0 and max_brightness. This file will also 183c4c1b69SCorentin Chary show the brightness level stored in the driver, which 193c4c1b69SCorentin Chary may not be the actual brightness (see actual_brightness). 203c4c1b69SCorentin CharyUsers: HAL 213c4c1b69SCorentin Chary 223c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/actual_brightness 233c4c1b69SCorentin CharyDate: March 2006 243c4c1b69SCorentin CharyKernelVersion: 2.6.17 253c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 263c4c1b69SCorentin CharyDescription: 273c4c1b69SCorentin Chary Show the actual brightness by querying the hardware. 283c4c1b69SCorentin CharyUsers: HAL 293c4c1b69SCorentin Chary 303c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/max_brightness 313c4c1b69SCorentin CharyDate: April 2005 323c4c1b69SCorentin CharyKernelVersion: 2.6.12 333c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 343c4c1b69SCorentin CharyDescription: 353c4c1b69SCorentin Chary Maximum brightness for <backlight>. 363c4c1b69SCorentin CharyUsers: HAL 37*bb7ca747SMatthew Garrett 38*bb7ca747SMatthew GarrettWhat: /sys/class/backlight/<backlight>/type 39*bb7ca747SMatthew GarrettDate: September 2010 40*bb7ca747SMatthew GarrettKernelVersion: 2.6.37 41*bb7ca747SMatthew GarrettContact: Matthew Garrett <mjg@redhat.com> 42*bb7ca747SMatthew GarrettDescription: 43*bb7ca747SMatthew Garrett The type of interface controlled by <backlight>. 44*bb7ca747SMatthew Garrett "firmware": The driver uses a standard firmware interface 45*bb7ca747SMatthew Garrett "platform": The driver uses a platform-specific interface 46*bb7ca747SMatthew Garrett "raw": The driver controls hardware registers directly 47*bb7ca747SMatthew Garrett 48*bb7ca747SMatthew Garrett In the general case, when multiple backlight 49*bb7ca747SMatthew Garrett interfaces are available for a single device, firmware 50*bb7ca747SMatthew Garrett control should be preferred to platform control should 51*bb7ca747SMatthew Garrett be preferred to raw control. Using a firmware 52*bb7ca747SMatthew Garrett interface reduces the probability of confusion with 53*bb7ca747SMatthew Garrett the hardware and the OS independently updating the 54*bb7ca747SMatthew Garrett backlight state. Platform interfaces are mostly a 55*bb7ca747SMatthew Garrett holdover from pre-standardisation of firmware 56*bb7ca747SMatthew Garrett interfaces. 57