Intel graphics card brightness control issue
Ethan W. House
ehouse at csh.rit.edu
Wed Sep 4 16:14:38 UTC 2013
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
I have a Lenovo Thinkpad x230.
I will start playing around with acpidump after work.
On Wed, Sep 4, 2013 at 1:30 AM, Matthias Petermann <matthias at petermann-it.de
> 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
>> might be related but I am not sure.
>> I found a couple of other email chains with similar issues but most of
>> have been inactive for more then a year.
> Which Laptop model do you have? This issue appears a bit familiar to me
> - I have the same on my Thinkpad. As a workaround you could try to change
> the brightness by direct ACPI calls.
> * 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.
> Kind regards,
>  http://www.freebsd.org/cgi/**query-pr.cgi?pr=amd64/181357<http://www.freebsd.org/cgi/query-pr.cgi?pr=amd64/181357>
>  http://www.freebsd.org/doc/en_**US.ISO8859-1/books/handbook/**
> Matthias Petermann <matthias at petermann-it.de>
> Ihr Partner für anspruchsvolle IT-Lösungen
> www.petermann-it.de - lösungsorientiert, innovativ und erfolgreich
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