It does not start when pulseaudio is disabled on my system. It does start after reenabling pulseaudio, however, gnome-volume-control-applet doesn't run at all.

It works fine here. (I get the error message when I try to start a second gnome-volume-control-applet)

[pterjan@coin ~]$ gnome-volume-control-applet         
** (gnome-volume-control-applet:2557): DEBUG: Updating client: index=0 name='ConsoleKit Session /org/freedesktop/ConsoleKit/Session2'
** (gnome-volume-control-applet:2557): DEBUG: Updating client: index=4 name='GNOME Volume Control'
** (gnome-volume-control-applet:2557): DEBUG: Updating sink: index=0 name='alsa_output.pci_10de_59_alsa_playback_0' description='NVidia CK804 - NVidia CK804' map='front-left,front-right'
** (gnome-volume-control-applet:2557): DEBUG: Changing volume for sink: n=2 vol=65536
** (gnome-volume-control-applet:2557): DEBUG: Channel 0 v=65536
** (gnome-volume-control-applet:2557): DEBUG: Channel 1 v=65536
** (gnome-volume-control-applet:2557): DEBUG: Updating source: index=0 name='alsa_output.pci_10de_59_alsa_playback_0.monitor' description='Monitor of NVidia CK804 - NVidia CK804'
** (gnome-volume-control-applet:2557): DEBUG: Updating source: index=1 name='alsa_input.pci_10de_59_alsa_capture_0' description='NVidia CK804 - NVidia CK804'
[1]+  Stopped                 gnome-volume-control-applet
[pterjan@coin ~]$ bg
[1]+ gnome-volume-control-applet &
[pterjan@coin ~]$ gnome-volume-control-applet

** (gnome-volume-control-applet:2701): WARNING **: Failed to acquire org.gnome.VolumeControlApplet

** (gnome-volume-control-applet:2701): WARNING **: Could not acquire name on session bus
[pterjan@coin ~]$ 

Pascal, do you have pulseaudio running?

The volume control slider works okay for me, but the "Volume Control..." button doesn't do anything. Is there a way to start the Event Sound properties from the terminal?

Do I have PulseAudio running? ABSOLUTELY NOT. I do not have it installed/running, nor do I want it on my system. The same goes with ALSA (I use OSS4).

(In reply to comment #2)
> It works fine here. (I get the error message when I try to start a second
> gnome-volume-control-applet)
> 

Same here. This confused me quite a bit, the applet was in fact running on my system but not showing any tray icon. Could the error message be modified to reflect this case, e.g. check if a process is already running and then just print that info?

OK I had pulseaudio autostarting even if I had disabled it long ago, indeed it does not start when pulseaudio is not running :

** (gnome-volume-control-applet:12914): WARNING **: Connection failed

Did pulseaudio become mandatory for gnome desktop ?

Could be mandatory if pulseaudio was enabled at build time.

The is a test in configure but build will fail if we don't have it :

#include <pulse/pulseaudio.h>
#include <pulse/glib-mainloop.h>
#include <pulse/ext-stream-restore.h>

And code only knows about pulseaudio

So it is indeed mandatory...

it is actually explicit:

if HAVE_PULSEAUDIO
SUBDIRS += gnome-volume-control
endif

Created attachment 128462 [details] [review]
gvc-start-cancel.patch

If PulseAudio can't be contacted, this dialogue pops up, allowing the user to cancel the start of the mixer.

On my system, PulseAudio will usually start after a couple more seconds when it's not running.

Would like help on the wording of the "Waiting for PulseAudio" dialogue.

2009-02-12  Bastien Nocera  <hadess@hadess.net>

        * src/dialog-main.c (on_control_ready), (warning_dialog_answered),
        (dialog_popup_timeout), (main): When PulseAudio isn't running,
        or takes a long time to connect to, popup a dialogue telling
        the user what we're waiting for, and the ability to cancel
        (Closes: #566835)

Hmm... I stull don't see anything happening on the panel tray or popup windows etc... but:

$ gnome-volume-control-applet 

** (gnome-volume-control-applet:15581): WARNING **: Applet is already running, exiting

(In reply to comment #12)
> Hmm... I stull don't see anything happening on the panel tray or popup windows
> etc... but:
> 
> $ gnome-volume-control-applet 
> 
> ** (gnome-volume-control-applet:15581): WARNING **: Applet is already running,
> exiting

There's a gnome-panel (or GTK+, or notification area) bug. A number of status icon don't show up.

(In reply to comment #10)

> Would like help on the wording of the "Waiting for PulseAudio" dialogue.

The wording would probably be similar to the metacity dialog when a window doesn't respond to the close signal.