[LAD] Trouble setting h/w MIDI device as output port

I've been stumped for a while as to why my Tascam US-122 box stopped working as a writeable midi port. Using Debian Wheezy, everything was working up to a few weeks ago. MIDI input still works and there's nothing suspicious in the /var/logs. But... nick@arial:~$ aplaymidi -l Port Client name Port name 14:0 Midi Through Midi Through Port-0 20:0 TASCAM US-X2Y TASCAM US-X2Y MIDI 1 24:0 USB MIDI keyboard USB MIDI keyboard MIDI 1 nick@arial:~$ aplaymidi -p 20:0 Desktop/076903b_.mid Cannot connect to port 20:0 - Input/output error nick@arial:~$ uname -a Linux arial 3.2.0-4-686-pae #1 SMP Debian 3.2.32-1 i686 GNU/Linux Using older kernels doesn't help. Connecting e.g. rosegarden to the TASCAM US-122 in qjackctl fails silently (the link is not made in the connections window and nothing is printed on the console). Can't see any module loading issues. Is anybody else seeing this behaviour? I'd submit a bug report but really can't figure out exactly what isn't working :( nick@arial:~$ lsmod Module Size Used by snd_usb_audio 71309 0 snd_hrtimer 12540 0 snd_seq_dummy 12455 0 snd_usb_usx2y 22748 2 snd_usbmidi_lib 18844 2 snd_usb_audio,snd_usb_usx2y snd_seq_midi 12744 0 snd_seq_midi_event 13124 1 snd_seq_midi snd_rawmidi 18376 2 snd_seq_midi,snd_usbmidi_lib ... usbcore 104470 8 ehci_hcd,uhci_hcd,uas,usb_storage,snd_usb_audio,snd_usbmidi_lib,snd_usb_usx2y usb_common 12338 1 usbcore Nick/.