Simplify volume setting at startup/shutdown

Currently, on a normal desktop session, volume is set four times on startup - initally by the kernel, then by alsactl, then by PulseAudio in the DM session, then by PulseAudio in the logged in session.

When shutting down, both PulseAudio and alsactl saves volumes to restore them later. And then we also have suspend and hibernate to consider, and that cards can be plugged in at any time.

First, isn't this quite complex for something as simple as setting volumes? Second, can we facilitate new features, such as 1) having a "set this volume as default, for all users, on startup" button in the volume control, or 2) "allow the DM user to introspect different users' volumes"?

Topic Lead: David Henningsson (<email address hidden>)
Working for Canonical with audio hardware enablement, fixing audio bugs and maintaining the audio stack, and also part of PulseAudio's current development team.