Re: ACPI display brightness on Lenovo Thinkpad T430s

[nia <nia%NetBSD.org@localhost>]

On Wed, Mar 10, 2021 at 11:23:50AM +0100, Fekete Zoltn wrote:
> Hi There,
> 
> Please give me advice how to proceed in the topic below. I want to have the
> display brightness working.
> 
> I have traced the route of the brightness buttonpress (up or down) in the
> acpi subsystem in the kernel on my laptop. Everything seems to be alright.
> The driver takes the button press, translates into an acpi code, then it
> calls the acpi driver, which sends the code to the hardware.
> The brightness of the display is not changing, however.
> 
> Does anybody know what to do?

I think the brightness tweaking bits were broken when DRM was updated
for NetBSD 9.0, we have another chance to get it right for the next
DRM update. Modifying the hw.acpi.acpiout0.brightness sysctl should
not do nothing.

Currently, I use sysutils/intel-backlight from pkgsrc. It performs
raw access to PCI device nodes, so needs root and kern.securelevel=0
unfortunately.