Thanks to Emiel Kollof (sorry I screwed up attribution!), AC97 support has been synced up with FreeBSD, plus support for the following devices has been added by Jeroen Ruigrok:
Diamond Technology Monster (DT0398)
Intersil (Harris) HMP9701
Integrated Technology Express (ITE) ITE2226E and ITE2646E
Texas Instruments TLC320AD90
Winbond W83971D
Asahi Kasei AK4544A and AK4545
Realtek ALC850
Wolfson WM9711L, WM9712L, and WM9709
Texas Instruments’ TLV320AIC27
Conexant SmartDAA HSD11246