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Date:      Wed, 04 Sep 2013 09:14:35 -0700
From:      "Ethan W. House" <ehouse@csh.rit.edu>
To:        Matthias Petermann <matthias@petermann-it.de>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Intel graphics card brightness control issue
Message-ID:  <CAFRryZhoE1prB+tzfu6LkBzkHwfC7Tsw5wkJw456EoT+3kP4Xw@mail.gmail.com>
In-Reply-To: <20130904103044.Horde.cIfa0FIz0Yk1WO9-khv0NQ1@d2ux.org>
References:  <CAFRryZiFY0Pxh8oomzPPikn7hZ34F8N6smw-3BCDnDGHvas_Bw@mail.gmail.com> <20130904103044.Horde.cIfa0FIz0Yk1WO9-khv0NQ1@d2ux.org>

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I get a "Unknown object type '0'" error. Which interestingly enough is very
similar to the error I get when I use xbacklight "No outputs have backlight
property".

I have a Lenovo Thinkpad x230.

I will start playing around with acpidump after work.


Ethan House

On Wed, Sep 4, 2013 at 1:30 AM, Matthias Petermann <matthias@petermann-it.d=
e
> wrote:

> Hi Ethan,
>
> Zitat von "Ethan W. House" <ehouse@csh.rit.edu>:
>
>
>  What could be causing my brightness control to not work on my Intel
>> graphics card. The acpi values change but no effect takes place.
>>
>> ehouse@derpy ~ $ sudo sysctl hw.acpi.video.lcd0.brightness=3D**50
>> hw.acpi.video.lcd0.brightness: 100 -> 50
>> ehouse@derpy ~ $ sudo sysctl hw.acpi.video.lcd0.active=3D1
>> hw.acpi.video.lcd0.active: 0 -> 0
>>
>> I also have an issue were upon resume by machine reboots. I believe the
>> two
>> might be related but I am not sure.
>>
>> I found a couple of other email chains with similar issues but most of
>> them
>> have been inactive for more then a year.
>>
>
> Which Laptop model do you have? This issue appears a bit familiar to me[1=
]
> - I have the same on my Thinkpad. As a workaround you could try to change
> the brightness by direct ACPI calls.
>
> Preparation:
>
> * install sysutils/acpi_call
> * kldload acpi_call
>
> Change brightness:
>
> * acpi_call -p '\VBRU'   (Brightness Up)
> * acpi_call -p '\VBRD'   (Brightness Down)
>
> It might be that these calls are specific to Thinkpads, not sure if they
> work with others. You can try to find out with acpidump[1].
>
> Kind regards,
> Matthias
>
> [1] http://www.freebsd.org/cgi/**query-pr.cgi?pr=3Damd64/181357<http://ww=
w.freebsd.org/cgi/query-pr.cgi?pr=3Damd64/181357>
> [2] http://www.freebsd.org/doc/en_**US.ISO8859-1/books/handbook/**
> acpi-debug.html<http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook=
/acpi-debug.html>
> --
> Matthias Petermann <matthias@petermann-it.de>
> Ihr Partner f=FCr anspruchsvolle IT-L=F6sungen
> www.petermann-it.de - l=F6sungsorientiert, innovativ und erfolgreich
>
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