Re: NetBSD 9.3 amd64 won't turn off display backlight

[RVP <rvp%SDF.ORG@localhost>]

On Mon, 23 Jan 2023, Damien Boureille wrote:

> Thanks. I tried that, however this has dependencies on X, and even then, it wouldn't work.

If you mean the dependency on libdrm, then that can be eliminated.
The code just needs libpciaccess.

> I also tried blacklisting i915drmdkms, booting from both BIOS and UEFI, and using genfb instead of acpivga.

genfb won't work here. It's the DRMKMS driver (for intel) that does
brightness control. Since that isn't working (yet), we use
`intel_backlight' which fiddles with the PCI registers in the same
way (but directly).

I could understand the newer intel cards not working because they
have newer PCHs (Platform Controller Hubs), but, your card is old
enough that it should've worked.

- What error (if any) did intel_backlight produce?

- Can you post a complete dmesg output?

- And a full `pcictl pci0 list'

so that we can see what PCH you have?

-RVP