1. Kenwood AFINA RD-VH7PC
2. 6-STABLE
3.uhub5: Atmel Standard USB Hub, class 9/0, rev 1.10/3.00, addr 2
uhub5: 4 ports with 4 removable, bus powered
ugen0: Mitsubishi product 0x1001, rev 1.00/1.00, addr 3　←三菱のはなんだろう？
uaudio0: Kenwood Kenwood Audio Device, rev 1.00/0.01, addr 4
uaudio_identify_ac: skip desc type=0x04
uaudio0: ignored setting with precision 20　←４行ある
uaudio0: audio rev 1.00
pcm1: <USB Audio> on uaudio0

4. device snd_uaudio を追加。cat /dev/sndstat すると、
pcm1: <USB Audio> at addr ? (1p/1r/2v channels duplex)
mode 1:(output) 1ch, 8/8bit, pcm, 4990-55010Hz
mode 2:(output) 2ch, 8/8bit, pcm, 4990-55010Hz
mode 3:(output) 1ch, 16/16bit, pcm, 4990-55010Hz
mode 4:(output) 2ch, 16/16bit, pcm, 4990-55010Hz
mode 1:(input) 1ch, 8/8bit, pcm, 44100Hz
mode 2:(input) 2ch, 8/8bit, pcm, 44100Hz
mode 3:(input) 1ch, 16/16bit, pcm, 44100Hz
mode 4:(input) 2ch, 16/16bit, pcm, 44100Hz
mixer -f /dev/mixer1 すると、vol がないのね。
Mixer bass is currently set to 50:50
Mixer treble is currently set to 50:50
Mixer speaker is currently set to 75:75
Recording source: mic

5. 出力は動く。入力は試してない。
usbdevs -v はこんな感じ。
port 1 addr 2: full speed, power 64 mA, config 1, Standard USB Hub(0x3301), Atmel(0x03eb), rev 3.00
port 1 addr 3: full speed, power 100 mA, config 1, product 0x1001(0x1001), Mitsubishi(0x0b28), rev 1.00
port 2 addr 4: full speed, power 100 mA, config 1, Kenwood Audio Device(0x1002), Kenwood(0x0b28), rev 0.01