Inspiron 1525 with Linux

I've had this computer for a year - it shipped with Ubuntu 8.04. I've since upgraded to 9.10 but I've never been able to get audio.

Initially that wasn't an issue but now I'm really missing it. All my attempts at identifying and installing what I'm missing have failed. The system is fine with Windows XP and Vista - so there's no hardware problem. Dell and other Diagnostics shows everything is fine.

There is no package in the linux community (via Synaptic package manager anyway) that relates to the Sigmatel sound system - which is what is installed on this particular laptop. Nor any web search I've made has helped. Dell support doesn't have an answer.

Has anyone run into the same issue? Interestingly the Ubuntu bootup chimes are working - but that's all. I see no /dev/audio entry which I think I should have?