No audio from VIA azalia codecs

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

Just got a new machine which has a VIA azalia codec (NetBSD doesn't 
currently explicitly support any VIA codecs), but I can't get any sound 
out of it. I tried enabling the generic mixer code:

--- sys/dev/pci/azalia_codec.c  2 Mar 2009 20:16:34 -0000       1.71.4.3
+++ sys/dev/pci/azalia_codec.c  27 Apr 2009 11:01:08 -0000
@@ -254,6 +254,12 @@
                this->init_widget = alc888_init_widget;
                this->mixer_init = alc888_mixer_init;
                break;
+       case 0x11061708:
+               this->name = "VIA VT1708/A";
+               this->init_dacgroup = generic_codec_init_dacgroup;
+               this->mixer_init = generic_mixer_autoinit;
+               this->init_widget = generic_mixer_init_widget;
+               break;
        case 0x11d41981:
                /* http://www.analog.com/en/prod/0,2877,AD1981HD,00.html */
                this->name = "Analog Devices AD1981HD";

This got me a sensible looking list of mixer items (previously they were 
all colours):
record.adc15.mute=off
record.adc15=252,252
mix.mix17.dac10.mut=off
mix.mix17.mic.mute=off
mix.mix17.imic.mute=off
mix.mix17.dac13.mut=off
mix.mix17.dac10=176,176
mix.mix17.mic=120,120
mix.mix17.imic=120,120
mix.mix17.dac13=120,120
inputs.sel18.source=mix17
outputs.sel19.mute=off
outputs.sel19=126,126
outputs.sel1a.mute=off
outputs.sel1a=126,126
outputs.sel1b.mute=off
outputs.sel1b=126,126
outputs.mic.dir=input
outputs.ispkr.mute=off
outputs.ispkr=126,126
outputs.ispkr.boost=off
outputs.imic.dir=input
record.adc27.mute=off
record.adc27=120,120
playback.mode=10
record.mode=15
outputs.master=176,176
inputs.dac=176,176
record.volume=252,252

I've tried setting outputs.ispkr.boost to on and maxing out 
outputs.master, outputs.ispkr and inputs.dac to no avail.

dmesg (wuth above patch):
azalia0 at pci4 dev 1 function 0: Generic High Definition Audio Controller
azalia0: interrupting at ioapic0 pin 17
azalia0: host: 0x1106/0x3288 (rev. 16), HDA rev. 1.0
azalia0: codec[0]: VIA VT1708/A (rev. 7.0), HDA rev. 1.0
azalia0: codec[1]: 0x1057/0x3055 (rev. 7.0), HDA rev. 1.0
azalia0: codec[1]: No support for modem function groups
azalia0: codec[1] has no audio function groups
audio0 at azalia0: full duplex, independent

Unless I'm missing something, FreeBSD's driver which claims to 
support this device doesn't have any specific quirks, but the Linux ALSA 
project has a whole bunch:

http://git.alsa-project.org/?p=alsa-kernel.git;a=blob;f=sound/pci/hda/patch_via.c;h=b25a5cc637d6072cbbad235753d64ff6c12c3ff1;hb=HEAD

--
Stephen