Midi keyboard doesn't work in LMMS in Debian Linux. It appears in LMMS as Input, but performs no sound when a key is pressing. I tried using QJackCtl, "a2jmidid -e" and most available options.
LMMS settings:
sound driver = Jack
midi driver = ALSA seq
QJackCtl settinhs:
driver = ALSA
midi driver = seq
ALSA seq support enabled
Output of a2jmidid -e:
JACK MIDI <-> ALSA sequencer MIDI bridge, version 8 (7383d268c4bfe85df9f10df6351677659211d1ca) built on Thu Jan 1 05:00:00 1970
Copyright 2006,2007 Dmitry S. Baikov
Copyright 2007,2008,2009,2011,2012 Nedko Arnaudov
Bridge starting...
Using JACK server 'default'
Hardware ports will be exported.
Cannot lock down 82274202 byte memory area (Cannot allocate memory)
Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
JackClient::AcquireSelfRealTime error
Bridge started
Press ctrl-c to stop the bridge
port created: Midi Through [14] (capture): Midi Through Port-0
port created: Midi Through [14] (playback): Midi Through Port-0
port created: GarageKey mini [20] (capture): GarageKey mini MIDI 1
port created: GarageKey mini [20] (playback): GarageKey mini MIDI 1
port created: LMMS [131] (playback): TripleOscillator
ERROR: a2j_port_create: jack_port_register() failed for 'LMMS [131] (playback): TripleOscillator'
ERROR: a2j_port_create: jack_port_register() failed for 'LMMS [131] (playback): TripleOscillator'
ERROR: a2j_port_create: jack_port_register() failed for 'LMMS [131] (playback): TripleOscillator'
LMMS settings:
sound driver = Jack
midi driver = ALSA seq
QJackCtl settinhs:
driver = ALSA
midi driver = seq
ALSA seq support enabled


Output of a2jmidid -e:
JACK MIDI <-> ALSA sequencer MIDI bridge, version 8 (7383d268c4bfe85df9f10df6351677659211d1ca) built on Thu Jan 1 05:00:00 1970
Copyright 2006,2007 Dmitry S. Baikov
Copyright 2007,2008,2009,2011,2012 Nedko Arnaudov
Bridge starting...
Using JACK server 'default'
Hardware ports will be exported.
Cannot lock down 82274202 byte memory area (Cannot allocate memory)
Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
JackClient::AcquireSelfRealTime error
Bridge started
Press ctrl-c to stop the bridge
port created: Midi Through [14] (capture): Midi Through Port-0
port created: Midi Through [14] (playback): Midi Through Port-0
port created: GarageKey mini [20] (capture): GarageKey mini MIDI 1
port created: GarageKey mini [20] (playback): GarageKey mini MIDI 1
port created: LMMS [131] (playback): TripleOscillator
ERROR: a2j_port_create: jack_port_register() failed for 'LMMS [131] (playback): TripleOscillator'
ERROR: a2j_port_create: jack_port_register() failed for 'LMMS [131] (playback): TripleOscillator'
ERROR: a2j_port_create: jack_port_register() failed for 'LMMS [131] (playback): TripleOscillator'