CONFIG_AC97_BUS (not configurable)

modulename: ac97_bus.ko

configname: CONFIG_AC97_BUS

Linux Kernel Configuration
└─>Device Drivers
└─>AC97_BUS
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This is used to avoid config and link hard dependencies between the
sound subsystem and other function drivers completely unrelated to
sound although they're sharing the AC97 bus. Concerned drivers
should "select" this.

source code:
sound/ac97_bus.c