CONFIG_SND_OPL4_LIB (not configurable)

modulename: snd-opl4-lib.ko

and/or

snd-opl3-lib.ko

configname: CONFIG_SND_OPL4_LIB

Linux Kernel Configuration
└─>Device Drivers
└─>Sound
└─>Advanced Linux Sound Architecture
└─>Generic devices
└─>SND_OPL4_LIB
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
source code:
sound/drivers//opl3//