OK, its clear from that that the modules are NOT loaded when you first boot, but alsaconf loads the required modules.
Its possible we can solve this by inserting an appropriate entry in your /etc/modprobe.d/sound file. Typically
yast > hardware > sound will configure your /etc/modprobe.d/sound file (but if I recall, this wasn't working properly on your pc). My memory may be faulty here, ... you could try
yast > hardware > sound to configure your sound ... worst case (if that doesn't work) is we just undo what it does.
Also, please, can you post the contents of that /etc/modprobe.d/sound file? Also check its contents before sound is working, and after sound is working, and advise if there are any differences.