[CentOS] Headphone on a Acer Extensa 5220

Hello,

is there any chance to get a headphone working under a acer extensa 5220
with CenOS 5.2 (2.6.18-92.1.6.el5) installed? Maybe by centosplus or
self compiled alsa sources?

# rpm -qa | grep alsa
alsa-lib-1.0.14-1.rc4.el5
alsa-utils-1.0.14-3.rc4.el5

The sound works great on this notebook and the hardware is detected
as 'Intel Corporation 82801H (ICH8 Family) HD Audio Controller
snd-hda-intel'. But the only settings alsamixer shows are 'Master'
and 'PCM', nothing about Headphone or Microphone.

Microphone is not so important, but a working headphone on the notebook
would be great. Any ideas to get it working?
Thank you very much!


regards
Olaf