1*d55c028fSMatthias KaehlckeWhat: /sys/class/backlight/<backlight>/scale 2*d55c028fSMatthias KaehlckeDate: July 2019 3*d55c028fSMatthias KaehlckeKernelVersion: 5.4 4*d55c028fSMatthias KaehlckeContact: Daniel Thompson <daniel.thompson@linaro.org> 5*d55c028fSMatthias KaehlckeDescription: 6*d55c028fSMatthias Kaehlcke Description of the scale of the brightness curve. 7*d55c028fSMatthias Kaehlcke 8*d55c028fSMatthias Kaehlcke The human eye senses brightness approximately logarithmically, 9*d55c028fSMatthias Kaehlcke hence linear changes in brightness are perceived as being 10*d55c028fSMatthias Kaehlcke non-linear. To achieve a linear perception of brightness changes 11*d55c028fSMatthias Kaehlcke controls like sliders need to apply a logarithmic mapping for 12*d55c028fSMatthias Kaehlcke backlights with a linear brightness curve. 13*d55c028fSMatthias Kaehlcke 14*d55c028fSMatthias Kaehlcke Possible values of the attribute are: 15*d55c028fSMatthias Kaehlcke 16*d55c028fSMatthias Kaehlcke unknown 17*d55c028fSMatthias Kaehlcke The scale of the brightness curve is unknown. 18*d55c028fSMatthias Kaehlcke 19*d55c028fSMatthias Kaehlcke linear 20*d55c028fSMatthias Kaehlcke The brightness changes linearly with each step. Brightness 21*d55c028fSMatthias Kaehlcke controls should apply a logarithmic mapping for a linear 22*d55c028fSMatthias Kaehlcke perception. 23*d55c028fSMatthias Kaehlcke 24*d55c028fSMatthias Kaehlcke non-linear 25*d55c028fSMatthias Kaehlcke The brightness changes non-linearly with each step. Brightness 26*d55c028fSMatthias Kaehlcke controls should use a linear mapping for a linear perception. 27