PowerBook G4 (5.9) Debian Sound problem

[Steffen Thoss <steffen@thoss4you.de>]

Hi !

I'm new to Linux on the PowerPC and have a problem with the sound on my
PowerBook (1.67 Ghz) Modell 5.9.
The problem is that the Gnome System sounds are working but all other
sound like mp3, DVD sound or radio streaming don't. Sometimes I just get
a noise and sometimes just nothing. I also have a constant low noise
from the speaker all the time. First I thought it's from the harddisk
but its from the speakers.
I'm running Debian unstable with the following modules loaded:

snd_aoa_codec_onyx     15616  2
snd_aoa_fabric_layout    14056  2
snd_aoa                20864  2 snd_aoa_codec_onyx,snd_aoa_fabric_layout
snd_aoa_i2sbus         24228  1
snd_pcm_oss            52032  1
snd_mixer_oss          20704  1 snd_pcm_oss
snd_pcm                91396  2 snd_aoa_i2sbus,snd_pcm_oss
snd_timer              26500  1 snd_pcm
snd_page_alloc         11304  1 snd_pcm
snd                    65908  10 
snd_aoa_codec_onyx,snd_aoa_fabric_layout,snd_aoa,snd_aoa_i2sbus,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer
soundcore              11204  2 snd
snd_aoa_soundbus        8004  2 snd_aoa_fabric_layout,snd_aoa_i2sbus

Thank you for your help in advance.
Steffen