You may have to setup a file /etc/modprobe.d/snd-hda-intel.conf to specify a model to the snd-hda-intel kernel module. See /usr/src/linux/Documentation/sound/alsa/HD-Audio-Models.txt for alternatives.
If your Vaio uses the STAC9872 then try this
Code:
options snd-hda-intel model=vaio