Do an lsmod in the terminal. It should return something like this

```
Module Size Used by
bnep 17923 2
rfcomm 38408 12
ip6table_filter 12711 0
ip6_tables 22528 1 ip6table_filter
pci_stub 12550 1
vboxpci 22882 0
vboxnetadp 13328 0
vboxnetflt 27211 0
vboxdrv 251814 3 vboxpci,vboxnetadp,vboxnetflt
ipt_MASQUERADE 12663 3
iptable_nat 13016 1
nf_nat 24958 2 ipt_MASQUERADE,iptable_nat
nf_conntrack_ipv4 19084 4 iptable_nat,nf_nat
nf_defrag_ipv4 12649 1 nf_conntrack_ipv4
xt_state 12514 1
nf_conntrack 70103 5 ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4,xt_state
ipt_REJECT 12512 2
xt_CHECKSUM 12493 1
iptable_mangle 12646 1
xt_tcpudp 12531 5
iptable_filter 12706 1
ip_tables 18106 3 iptable_nat,iptable_mangle,iptable_filter
x_tables 21975 11 ip6table_filter,ip6_tables,ipt_MASQUERADE,iptable_nat,xt_state,ipt_REJECT,xt_CHECKSUM,iptable_mangle,xt_tcpudp,iptable_filter,ip_tables
bridge 79567 0
stp 12811 1 bridge
ppdev 12849 0
nvidia 10590610 40
btusb 18160 2
snd_es1938 19610 3
gameport 15060 2 snd_es1938
snd_opl3_lib 18863 1 snd_es1938
snd_hwdep 13276 1 snd_opl3_lib
snd_mpu401_uart 13865 1 snd_es1938
bluetooth 148839 23 bnep,rfcomm,btusb
snd_seq_midi 13132 0
snd_intel8x0 33318 3
snd_ac97_codec 106082 1 snd_intel8x0
ac97_bus 12642 1 snd_ac97_codec
gspca_zc3xx 51066 0
gspca_main 27610 1 gspca_zc3xx
snd_rawmidi 25241 2 snd_mpu401_uart,snd_seq_midi
snd_pcm 80435 3 snd_es1938,snd_intel8x0,snd_ac97_codec
videodev 85626 1 gspca_main
snd_seq_midi_event 14475 1 snd_seq_midi
snd_seq 51567 2 snd_seq_midi,snd_seq_midi_event
snd_timer 28932 3 snd_opl3_lib,snd_pcm,snd_seq
snd_seq_device 14172 4 snd_opl3_lib,snd_seq_midi,snd_rawmidi,snd_seq
i915 505159 1
snd 55902 23 snd_es1938,snd_opl3_lib,snd_hwdep,snd_mpu401_uart,snd_intel8x0,snd_ac97_codec,snd_rawmidi,snd_pcm,snd_seq,snd_timer,snd_seq_device
soundcore 12600 1 snd
snd_page_alloc 14115 2 snd_intel8x0,snd_pcm
drm_kms_helper 32889 1 i915
drm 192194 2 i915,drm_kms_helper
parport_pc 32114 1
binfmt_misc 17292 1
i2c_algo_bit 13199 1 i915
video 18908 1 i915
w83627hf 26767 0
hwmon_vid 12658 1 w83627hf
lp 17455 0
parport 40930 3 ppdev,parport_pc,lp
usbhid 41905 0
hid 77367 1 usbhid
8139too 23283 0
8139cp 22636 0
floppy 60310 0
```

If you don't see any MIDI related modules (the important ones are snd_seq_midi,snd_emu10k1_synth,snd_emux_synth,snd_ seq_oss,snd_seq,snd_emu10k1,snd_rawmidi),
then that means ALSA hasn't been configured properly. Try `sudo modprobe`

for these modules, and see what results.