There's a CS4231 codec for WSS compatibility. It also has a Sound Blaster compatibility mode which only operates at 8-bit. I chose to use the WSS driver. The Inspiron's BIOS by default sets the audio IRQ to 05. So use 07, or 09.
Sound support is, sadly, far from perfect.
To add insult to injury, nothing short of a cold reboot will make it recover the interrupt. I believe this can somehow be solved using isapnptools , but I haven't the time to try that out - if I'm not mistaken, 0x530 is out of the range that pnpdump will probe. I'm using nxterm instead. There is a Linux program called tpconfig that can control the behaviour of the Synaptics Touchpad. However, tpconfig is programmed upon the API of older touchpads with four mode bytes.