snd_ich: S/PDIF output not working

Hi,

my noteboot (Samsung X05) has an spdif connector, which works under WinXP 
but doesn't on FreeBSD-current. Sound hardware is this:

pcm0: <Intel ICH4 (82801DB)> port 0x18c0-0x18ff,0x1c00-0x1cff mem 0xe0100800-0xe01008ff,0xe0100c00-0xe0100dff irq 10 at device 31.5 on pci0
pcm0: [GIANT-LOCKED]
pcm0: <SigmaTel STAC9752/53 AC97 Codec>

I'm digging through the registers of the codec and as far as I can see it,
spdif should be enabled, at least from the codec's point of view. But I 
can't see anything happening, no red light, nothing at the receiving end. 
The digital output has to be enabled by <Fn><F7> but this doesn't work.

Is there anyone with some hint where I could try to look next?

I've hacked up ac97.c a little to produce a register dump of the codec as
last step from ac97_initmixer(). Here it is, maybe someone else can make
any clues from it.

Reg : Value
00  : 6a90
02  : 8000
04  : 8000
06  : 8000
08  : 0000
0a  : 0000
0c  : 8008
0e  : 8008
10  : 8808
12  : 8808
14  : 8808
16  : 8808
18  : 8808
1a  : 0000
1c  : 8000
1e  : 0000
20  : 0000
22  : 0000
24  : 0000
26  : 000f
28  : 0a05
2a  : 0414
2c  : bb80
2e  : 0000
30  : 0000
32  : bb80
34  : 0000
36  : 0000
38  : 0000
3a  : a004
3c  : 0000
3e  : 0100
40  : 0000
42  : 0000
44  : 0000
46  : 0000
48  : 0000
4a  : 0000
4c  : 0003
4e  : ffff
50  : 0000
52  : 0000
54  : 0000
56  : 0000
58  : 0000
5a  : 0000
5c  : 0000
5e  : 0000
60  : 0000
62  : 0000
64  : 0000
66  : 0000
68  : 0000
6a  : 0002
6c  : 0002
6e  : 1000
70  : 0000
72  : 0000
74  : 0800
76  : 0000
78  : 0000
7a  : 0000
7c  : 8384
7e  : 7652
 
-- 
Michael Lestinsky