Intel graphics card brightness control issue

[Ethan W. House]

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 at petermann-it.de
> wrote:

> Hi Ethan,
>
> Zitat von "Ethan W. House" <ehouse at 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 at derpy ~ $ sudo sysctl hw.acpi.video.lcd0.brightness=**50
>> hw.acpi.video.lcd0.brightness: 100 -> 50
>> ehouse at derpy ~ $ sudo sysctl hw.acpi.video.lcd0.active=1
>> 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=amd64/181357<http://www.freebsd.org/cgi/query-pr.cgi?pr=amd64/181357>
> [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 at petermann-it.de>
> Ihr Partner für anspruchsvolle IT-Lösungen
> www.petermann-it.de - lösungsorientiert, innovativ und erfolgreich
>
> ______________________________**_________________
> freebsd-questions at freebsd.org mailing list
> http://lists.freebsd.org/**mailman/listinfo/freebsd-**questions<http://lists.freebsd.org/mailman/listinfo/freebsd-questions>
> To unsubscribe, send any mail to "freebsd-questions-**
> unsubscribe at freebsd.org <freebsd-questions-unsubscribe at freebsd.org>"