dbus and system events - howto

[Vladimir Grebenschikov]

Hi 

I am wandering is there "right" way to pass "system" events, like
brightness buttons, volume buttons reported with devd to gnome desktop
to:
1. do appropriate changes (change volume, brightness, etc)
2. show nice informational popup (with volume bar and so on)
?

Before I had simple script, called from devd, it configures system with
xbacklight, mixer and sysctl's, and shows something with onscreend
daemon.

After Xorg update oscreend starts to freeze by some reason. So now I am
thinking about more "sane" way to link system events to gnome desktop.

Also xbacklight now does not works with radeonhd again.

So far I've dig for following dbus calls to manage brihgtness:
	/usr/local/bin/dbus-send --system --type=method_call --print-reply=1 \
		--dest=org.freedesktop.PowerManagement \
		--session /org/freedesktop/PowerManagement/Backlight \
		org.freedesktop.PowerManagement.Backlight.GetBrightness

	/usr/local/bin/dbus-send --system --type=method_call --print-reply=1 \
		--dest=org.freedesktop.PowerManagement \
		--session /org/freedesktop/PowerManagement/Backlight \
		org.freedesktop.PowerManagement.Backlight.SetBrightness uint32:$1

But, looks like they are not shows popup.
And I've not found simple solution about volume yet.

Hints will be appreciated.

PS:
  Side question, can dbus work without DISPLAY and XAUTHORITY initialized ?  
  (system bus ?, but above calls requires them)

PPS:
  8-CURRENT, Gnome, IBM T60.

-- 
Vladimir B. Grebenschikov
vova at fbsd.ru