CONFIG_SND_SEQ_MIDI (not configurable)

modulename: snd-seq-midi.ko

configname: CONFIG_SND_SEQ_MIDI

Linux Kernel Configuration
└─>Device Drivers
└─>Sound card support
└─>Advanced Linux Sound Architecture
└─>SND_SEQ_MIDI
In linux kernel since version 3.10 (release Date: 2013-06-30)  
source code:
sound/core//seq/