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: 6*a1cacb8aSThomas Zimmermann Control BACKLIGHT power, values are compatible with 7*a1cacb8aSThomas Zimmermann FB_BLANK_* from fb.h 898913408SMauro Carvalho Chehab 9*a1cacb8aSThomas Zimmermann - 0 (FB_BLANK_UNBLANK) : power on. 10*a1cacb8aSThomas Zimmermann - 4 (FB_BLANK_POWERDOWN) : power off 113c4c1b69SCorentin CharyUsers: HAL 123c4c1b69SCorentin Chary 133c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/brightness 143c4c1b69SCorentin CharyDate: April 2005 153c4c1b69SCorentin CharyKernelVersion: 2.6.12 163c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 173c4c1b69SCorentin CharyDescription: 183c4c1b69SCorentin Chary Control the brightness for this <backlight>. Values 193c4c1b69SCorentin Chary are between 0 and max_brightness. This file will also 203c4c1b69SCorentin Chary show the brightness level stored in the driver, which 213c4c1b69SCorentin Chary may not be the actual brightness (see actual_brightness). 223c4c1b69SCorentin CharyUsers: HAL 233c4c1b69SCorentin Chary 243c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/actual_brightness 253c4c1b69SCorentin CharyDate: March 2006 263c4c1b69SCorentin CharyKernelVersion: 2.6.17 273c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 283c4c1b69SCorentin CharyDescription: 293c4c1b69SCorentin Chary Show the actual brightness by querying the hardware. 303c4c1b69SCorentin CharyUsers: HAL 313c4c1b69SCorentin Chary 323c4c1b69SCorentin CharyWhat: /sys/class/backlight/<backlight>/max_brightness 333c4c1b69SCorentin CharyDate: April 2005 343c4c1b69SCorentin CharyKernelVersion: 2.6.12 353c4c1b69SCorentin CharyContact: Richard Purdie <rpurdie@rpsys.net> 363c4c1b69SCorentin CharyDescription: 373c4c1b69SCorentin Chary Maximum brightness for <backlight>. 383c4c1b69SCorentin CharyUsers: HAL 39bb7ca747SMatthew Garrett 40bb7ca747SMatthew GarrettWhat: /sys/class/backlight/<backlight>/type 41bb7ca747SMatthew GarrettDate: September 2010 42bb7ca747SMatthew GarrettKernelVersion: 2.6.37 43bb7ca747SMatthew GarrettContact: Matthew Garrett <mjg@redhat.com> 44bb7ca747SMatthew GarrettDescription: 45bb7ca747SMatthew Garrett The type of interface controlled by <backlight>. 46bb7ca747SMatthew Garrett "firmware": The driver uses a standard firmware interface 47bb7ca747SMatthew Garrett "platform": The driver uses a platform-specific interface 48bb7ca747SMatthew Garrett "raw": The driver controls hardware registers directly 49bb7ca747SMatthew Garrett 50bb7ca747SMatthew Garrett In the general case, when multiple backlight 51bb7ca747SMatthew Garrett interfaces are available for a single device, firmware 52bb7ca747SMatthew Garrett control should be preferred to platform control should 53bb7ca747SMatthew Garrett be preferred to raw control. Using a firmware 54bb7ca747SMatthew Garrett interface reduces the probability of confusion with 55bb7ca747SMatthew Garrett the hardware and the OS independently updating the 56bb7ca747SMatthew Garrett backlight state. Platform interfaces are mostly a 57bb7ca747SMatthew Garrett holdover from pre-standardisation of firmware 58bb7ca747SMatthew Garrett interfaces. 59