Heya,
Up to this point most distributions have been using different init scripts/udev rules files to save/restore mixer settings at boot/hotplug/shutdown. Please see my two attached patches for alsa-utils which add standardized, simplified support for this.
The first patch is stolen from Debian/Ubuntu, which moves asound.state to /var/lib, which is a more appropriate place, since /etc might be read-only.
The second patch includes a minimal udev rule (executed synchronously, enabled on all systems, regardless of systemd is used or not) and two systemd service files (executed asynchronously at boot/shutdown, only enabled if built with systemd support).
Given that most big distributions are moving to adopt systemd sooner or later it would be great to have support for this in the upstream package to avoid further balkanization how things are done here.
Lennart