lenovo b570 brightness control doesn't go to low brightness

[jac-tict]

Hi guys, on MacOSX with DSDT patched by macinsane B570 doesn't reach the minimum brightness.

 

I'm trying to look deeper, hope someone would help.

 

In Linux:

xrandr --prop | grep BACKLIGHT
BACKLIGHT: 16 (0x00000010) range:  (0,976)


sudo sh -c 'echo 16 > /sys/class/backlight/intel_backlight/brightness'

 

Gives the minimum brightness.

 

Hero DSDT:

Scope (_SB)
{
Device (PNLF)
{
Name (_HID, EisaId ("APP0002"))
Name (_CID, "backlight")
Name (_UID, 0x0A)
Name (_STA, 0x0B)
}  

 

 

Maybe the problem is that macosx use 10 steps and actual driver has different granularity/lowest values?

[Isopropylique]

I've found that my B570's minimum brightness is actually "off". If I press Fn + Insert enough times, the display can actually be turned off. The maximum is reached with Fn + Home about 3/4 of the way across the on-screen brightness indicator.