A debian user reported that volume control plugin doesn't work correctly when using multiple sound cards. It seems that except for default soundcard the plugins are not associated with the soundcard at Xfce startup (but it does save correctly which card they are configured too and the settings). For more information, you can see Debian bugreport at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=422433 Regards, -- Yves-Alexis Perez
This bug has also shown up Fedora with PulseAudio: https://bugzilla.redhat.com/show_bug.cgi?id=456887
I could imagine this being broken, I don't have more than one soundcard. Someone that does should check what it does at the loading code: "panel-plugin/mixer-preferences.gob" is the passive data class for the settings of the plugin. "panel-plugin/mixer-prefbox.gob" is the active object that represents the GUI of the panel plugin settings. Its function "fill_preferences" will be called, passing an instance of the mixer-preferences and at the end it will call "emit self_device_changed (self);". "device_changed" will then take care to set the currently active device using "vc_set_device" of the "libxfce4mixer". It will use what is in the entry of the device optionbox "self->device_cb->entry" in the GUI at that time. So put a g_warning("%s", txt) into function void device_changed (self) at mixer-prefbox.gob line 142, right after "txt" was assigned. on the shell call ./gobs make make install Run the panel with the plugin in a terminal (or just check ".xsession-errors"). Check what the g_warning actually outputs now.
*** Bug 4668 has been marked as a duplicate of this bug. ***
I cannot reproduce this, at least with version 4.9.0 it will correctly select the card it is configured to use on startup. The Debian report suggests that this was already fixed in version 4.6.0 or 4.8.0.