Re: Could not change brightness anymore with i915kms & acpi_video modules c 202211

--------
Emmanuel Vadot writes:
> On Thu, 02 Feb 2023 20:58:58 +0000
> "Poul-Henning Kamp" <phk@phk.freebsd.dk> wrote:
>
> > --------
> > parv/FreeBSD writes:
> > 
> > > > Does backlight(8) works for you?
> > >
> > > Thanks for the clue. It does! It does ...
> > >
> > > - I get the same number back via "backlight" without any arguments as
> > >   what I gave it earlier. There was no reporting of value being
> > >   subtracted by one;
> > 
> > Sorry for the delay in reporting back.
> > 
> > I consistently read one less back, except for 0 and 100.
>
>  Even 50 ?

	# backlight 
	brightness: 0
	# backlight 50
	# backlight
	brightness: 49
	# backlight 25
	# backlight
	brightness: 24
	# backlight 75
	# backlight
	brightness: 74

yes

>  So if you have, let's say brightness at 50%, and you plug an external
> monitor, brightness goes up to 100% ?

No, plugging and unplugging does not change the backlight.

But when the screen saver has kicked in, and I wake it up again, it comes
back at 100, (and reads back as 100)

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.