Re: GNOME 3.6 & Screen Brightness Extension

[Adam Tauno Williams <awilliam whitemice org>]

On Tue, 2012-10-30 at 00:36 +0100, Schubi wrote:
> Am 30.10.2012 00:25, schrieb Adam Tauno Williams:
> > I can adjust screen brightness via xrandr -
> > awilliam@workstation:~> xrandr --output VGA-1 --brightness 0.4
> > awilliam@workstation:~> xrandr --output VGA-1 --brightness 0.9
> > awilliam@workstation:~> xrandr --output VGA-1 --brightness 1
> > But the screen brightness extension
> > <https://extensions.gnome.org/extension/231/brightness-control/> does
> > nothing.  Either on my laptop or my workstation.
> Works for me, running GNOME 3.6 on Ubuntu 64 bit.
> > Anyone know anything about this extension or how it goes about adjusting
> > brightness?
> Seems to be some DBUS magic. Dont know the exact method.
> > GNOME 3.6 openSUSE 12.2 x86_64

Yep, it looks like it uses the SetPercentage and GetPercentage  methods
of the org.gnome.SettingsDaemon.Power.Screen interface.

I verified on my laptop I can adjust the brightness of both displays.
xrandr --output LVDS1 --brightness 0.9
xrandr --output VGA1 --brightness 0.9

Using d-feet I can call SetPercentage and no change occurs.
Using StepUp() and StepDown() the result value *does* increment and
decrement, and appears to be preserved across invocations.  But, still,
no change occurs on the actual display.

Perhaps this really just sets the setting value and nobody is watching
the setting value?  Does anyone know how
org.gnome.SettingsDaemon.Power.Screen is *intended* to work?  Does it
attempt to call randr or does it just set a setting.