07 September, 2011

changing brightness from gnome shell

gnome-power-manager has been rewritten for GNOME 3.2, and is now merged into gnome-settings-daemon as a plugin and this manages policy. The power management is done by UPower for most parts, except backlight.This is managed at Session level by g-s-d via power plugin using XRandR or plain old sysfs depending upon driver support.

To manages screen brightness settings, one would do so via dbus, such as shown below 
$ gdbus call --session --dest org.gnome.SettingsDaemon --object-path /org/gnome/SettingsDaemon/Power --method org.gnome.SettingsDaemon.Power.Screen.GetPercentage

Now the question being, why bother at all with this aspect. On a tablet, this settings needs to be digged out and non-trivial to access. With gnome-shell-extension brightness ( http://people.redhat.com/rkhadgar/personal/gnome3-tablet/brightness.tar.xz ), you can manage the brightness from your desktop. This requires g-s-d to be patched to support "Changed" signal ( https://bugzilla.gnome.org/show_bug.cgi?id=658493 ).

On a side note, devs at gnome-shell are very helpful and felt good talking to them, along with rhughsie.

  • display brightness symbolic icon needs different levels, and one for auto setting.
  • Ambient Light Sensor support on linux seems spotty, and needs to be fixed.