[CentOS] No sound on HP 8540w, guidance requested

Sat May 7 19:32:41 UTC 2011
David <David at daku.org>

At 09:28 AM 5/7/2011, you wrote:
>On 07/05/11 16:22, David wrote:
> > Dear Experts
> >
> > I have been unsuccessful getting the sound to work on a HP Mobile
> > Workstation HP 8540w.
> >
> > Here's a brief rundown of where I am
> >
> > I did a clean new install of Centos 5.6 from DVD, using the Gnome
> > Desktop option and no optional modules.
> > I enabled the firewall, but disabled SELINUX.
> >
> > I installed three files from elrepo to make the wireless adaptor
> > work, and specified the video adaptor using the Gnome ->  System ->
> > Preferences ->  Display panel.
> >
>Hi David,
>If you're already familiar with elrepo then I'd suggest you try their
>updated alsa sound drivers.
>yum --enanlerepo=elrepo install kmod-alsa
>and reboot.
>Also, don't forget to check your sound device isn't muted. The ALSA docs
>Note: All mixer channels are muted by default. You must use a native
>        or OSS mixer program to unmute appropriate channels (for example a
>        mixer from the alsa-utils package).

I got two recommendations:
a) Used 'alsamixer' to unmute all channels.  The were, as a responder 
suggested, muted.
b) Installed kmod-alsa from elrepo.  It produced a bunch of warnings 
which I ignored.
c) I performed lspci | grep -i audio, and got

00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset 
High Definition Audio (rev 06)
01:00.1 Audio device: nVidia Corporation High Definition Audio 
Controller (rev a1)

No sound, and the mute button on the function display does nothing -- 
it's a constant orange color.
I am not sure where to go from here.