Documentation/ABI/testing/sysfs-class-backlight

   1 What:           /sys/class/backlight/<backlight>/scale
   2 Date:           July 2019
   3 KernelVersion:  5.4
   4 Contact:        Daniel Thompson <daniel.thompson@linaro.org>
   5 Description:
   6                 Description of the scale of the brightness curve.
   7
   8                 The human eye senses brightness approximately logarithmically,
   9                 hence linear changes in brightness are perceived as being
  10                 non-linear. To achieve a linear perception of brightness changes
  11                 controls like sliders need to apply a logarithmic mapping for
  12                 backlights with a linear brightness curve.
  13
  14                 Possible values of the attribute are:
  15
  16                 unknown
  17                   The scale of the brightness curve is unknown.
  18
  19                 linear
  20                   The brightness changes linearly with each step. Brightness
  21                   controls should apply a logarithmic mapping for a linear
  22                   perception.
  23
  24                 non-linear
  25                   The brightness changes non-linearly with each step. Brightness
  26                   controls should use a linear mapping for a linear perception.