[CentOS] Trouble running 'alsamixer' as normal user on headless box

Brian Kirkman

bkirkman at qwest.net
Fri Sep 11 21:08:34 UTC 2009


>Hi,
>
>I just transformed an old Pentium III 500 into a headless jukebox. It's
>installed in the basement, near the stereo. There's only a base CentOS
>system on it (GNOME unchecked, package customization checked and then
>everything unchecked). From there on, I just installed the ALSA utils,
>and vorbis-tools. The machine is only supposed to do one thing (and to
>do it well, UNIX philosophy :oD): fetch an audio stream (produced by
>MPD/Icecast upstairs on a big PC) and then output it from the soundcard
>to the AUX IN from the stereo.
>
>I have a partial - and near-total - success, in that everything runs
>fine... as root user. Whenever I try to run alsamixer as a normal user
>on that box, I get the following error message:
>
>[kikinovak at jukebox ~]$ alsamixer
>
>alsamixer: function snd_ctl_open failed for default: No such file or
>directory
>...
>
>Any idea what could be wrong here?
>
>Cheers from the hot south of France,

>Niki


I realize this is an old thread, but I, too, was building a standalone
jukebox last night and ran into this same issue.  I was trying to
configure the jukebox by SSHing into it, and I could only perform sound
tasks, including running alsamixer and mpd, as root.  Comparing to another
CentOS box, the jukebox's /dev/dsp was owned by root and the other CentOS
box's /dev/dsp was owned by the logged in user.  Aha, I figured I needed
to be logged in as a user to the physical jukebox machine in order to
grant ownership to the soundcard.  The jukebox had no user logged into it,
as it had just rebooted.  A solution, of course, would be to enable
autologin on the jukebox. I can't give the technical answer as to why this
happens, but just how it happens and how I managed to get it to work.  I
hope this helps.

-Brian



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