You probably need to manually modprobe one or more kernel sound drivers until you see something like this: $ lsmod
Module Size Used by Not tainted
snd_seq_midi 12288 0
snd_seq_midi_event 12288 1 snd_seq_midi
snd_seq 36864 2 snd_seq_midi,snd_seq_midi_event
snd_rawmidi 20480 1 snd_seq_midi
snd_seq_device 12288 3 snd_seq_midi,snd_seq,snd_rawmidi
You could start with: $ sudo modprobe snd_seq_device
This will create /dev/snd/seq