misc/185094: SIS 7012 sound card not working

[tt]

>Number:         185094
>Category:       misc
>Synopsis:       SIS 7012 sound card not working
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Dec 22 14:40:02 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     tt
>Release:        10.0-RC2
>Organization:
>Environment:
FreeBSD spiro 10.0-RC2 FreeBSD 10.0-RC2 #0 r259404: Sun Dec 15 11:45:13 UTC 2013     root at snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
Soundcard in an Acer Aspire 3000 laptop.

/dev/sndstat:

Installed devices:
pcm0: <SiS 7012> (play/rec) default


output of 'mixer':

Mixer vol      is currently set to  88:88
Mixer pcm      is currently set to  76:76
Mixer speaker  is currently set to  75:75
Mixer line     is currently set to  75:75
Mixer mic      is currently set to   0:0
Mixer cd       is currently set to  75:75
Mixer rec      is currently set to  75:75
Mixer igain    is currently set to   0:0
Mixer ogain    is currently set to  50:50
Mixer line1    is currently set to  75:75
Mixer phin     is currently set to   0:0
Mixer phout    is currently set to   0:0
Recording source: vol


mpg123 looks like its playing to the device, but not sound. catting a text file to /dev/dsp0.0 doesn't make any sound (either with headphones or with the onboard speakers). A cheap usb soundcard does work with this machine.
>How-To-Repeat:
Install FreeBSD 10.0-RC2 on an Acer Aspire 3000. Try to play an audio file of any description.
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: