ubuntu intrepid notes on sony vaio

I have tested intrepid on an vaio , an recent model with core2duo and geforce8600 (i don't remember de specs exactly)

All worked great (compiz, wireless ...) except when inserting the headphones (no sound in them)

so i had to add an line in

sudo nano /etc/modprobe.d/alsa-base

options snd-hda-intel model=vaio

(and then all was ok ) . I wonder why it wasn't detected