Possible bug in acpi_video(4)

[MrPhyber]

> > I tried the patch you sent, and I have a few questions:
> >
> > 1.  when will this patch be avaiable on 12.1-RELEASE?
>
> In stable/12 soon.
> In 12.1 probably never as the release has been released.
>
> > 2.  now the system does not spit out any more errors like
> >     the one complaining about _BQC missing: in fact it doesn't
> >     give errors at all, but the hardware brightness controls still
> >     won't work. Now hw.acpi.video.lcd0.active = 1 but if I try
> >     to modify hw.acpi.video.lcd0.brightness nothing appens. I
> >     still think that acpi_video doesn't see all video outputs
> >     (I investigated a bit further and on OpenBSD there are
> >     acpivouts on dmesg output, could be an hint). What could
> >     be wrong?
> >
>
> If your system is like mine then ACPI does not directly control the brightness.
> Instead, it posts some events that a video driver (like radeon or amdgpu) is
> supposed to listen to and then the driver should update the brightness.
> (This can also be thought of as the brightness being controlled by the video
> "card" / GPU rather than by a motherboard).
> For my laptop I had to patch amdgpu driver:
> https://github.com/FreeBSDDesktop/kms-drm/pull/241

Nevermind, after some thinkering I managed to get it to work on
drm-fbsd12.0-kmod. Now the hardware brightness controls work!
I am really grateful, thank you. I wonder when this patch will
be pushed upstream.
-MrPhyber