amd64/181357: LCD Brightness Control not working on Lenovo X121e (ACPI issue?)

[Zoran Kolic]

> I ran into similar problem with a X220. The ACPI brightness control can
> only be called directly with acpi_call. I bound the acpi_ibm brightness
> up/down events to a shell script using acpi_call with devd. It wroks
> except that the screen always turns on with maximum brightness if
> backlight had been deactivated by DPMS. I haven't found any convenient
> event to hook with devd for this case.

Out of curiosity, what happens if you go to bios and
try to change the value there. I set it that way on
my lenovo e320.
Best regards

                               Zoran