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

From: Poul-Henning Kamp <phk_at_phk.freebsd.dk>
Date: Tue, 31 Jan 2023 13:09:39 UTC
--------
Emmanuel Vadot writes:

> > > Does backlight(8) works for you?
> > 
> > Speaking of backlight(8):  On my T14s, I see the following:
> > 
> > If I set the light with backlight(8) to something, say 30%, and then
> > change the power-situation, for instance by unplugging the charger,
> > the backlight goes up to 100%.
> > 
> > If I then try to set it back to 30% with backlight(8), nothing happens.
> > 
> > If I use any other value, for instance 31%, backlight(8) does the job.
> > 
> > I guess somewhere some code says "It's always 30%, just return" ?
> > 
> > This might be a bit confusing if you have the intensity encoded in
> > some script, which then "sometimes does not work"...
>
>  Smells like
> https://cgit.freebsd.org/src/commit/sys/dev/backlight/backlight.c?id=e26ef41f79902991c772b59927c721aa7fa5fc64
>  It's not in 13.1 but will be in 13.2

I'm running

	14.0-CURRENT #0 main-n260119-7f2109f240c2: Mon Jan 16 22:54:18 UTC 2023

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Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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