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