2008/4/21 Stephen Wilkinson firstname.lastname@example.org:
OK, it's all explained in the source code referred to by Johannes Goecke (see above). In version 2.6.23 a "catch all VIA VT8237" function was used to enable the on-board sound card -- which is why it worked for me. In version 2.6.24 this was removed. Instead the DMI code (http://en.wikipedia.org/wiki/Desktop_Management_Interface) is used to enable the card *only* on MSI K8T Neo2 FIR. So once I've found the DMI code for my motherboard, I'll try a patch on the 2.6.24 kernel and post again if it works.
Status? I suggest posting this patch to LKML - this way it can be included in the vanilla kernel. ;)