[CentOS] sound problems... alsa & systemd?

Kay Schenk
Sun, 02 Apr 2017 17:31:21 -0000

On 03/29/2017 06:43 AM, ken wrote:
> On 03/28/2017 08:53 PM, ken wrote:
>> The www has failed me with this, so I'm trying you guys.  Sound
worked
>> great out of the box when I installed 7.2... Yay!  I could watch all
>> kinds of videos, like on facebook and youtube.  And I could listen to
>> most podcasts too.  But then something happened. It was either a
>> kernel upgrade or that I installed vlc (for watching videos on DVD)
>> and the whole stack of codecs for it... I don't know exactly when,
but
>> at some point I no longer had sound with youtube  and other web
>> videos.  The videos played fine, just no sound.  Note that using vlc,
>> both video and the audio with it play just fine.  I need to select the
>> audio driver (from a list in a vlc menu), however, else the sound
>> won't work in vlc either.
>>
>> If I go into the Applications menu, then System Tools -> Settings
->
>> Sound, under "Choose a device for sound output:" there are no
devices
>> listed.  There used to be.
>>
>> If I run "aplayer file.wav", nothing plays (no sound at all)
and I get
>> the error "main:786: audio open error: No such file or
directory".
>> If, on the other hand, I run "aplay file.wav -D plughw:0"
(i.e.,
>> specify the/a device), I do get sound, the file does play.
>>
>> I ran alsa-info.sh and it posted tons of info from it on my setup at
>>
http://www.alsa-project.org/db/?f=1dba91886be054df4816000768a0f5b109947a48.
>> Yet it still doesn't tell me what's missing.
>>
>> Anyone here have an idea...? or thoughts about where to look next?
>>
>> tia,
>> ken
>
> Still poking around my system for a solution, I found this comment at
> the top of /usr/lib/systemd/system/alsa-state.service and two other
> files in the same directory:
>
>> # Note that two different ALSA card state management schemes exist and
>> they
>> # can be switched using a file exist check -
>> /etc/alsa/state-daemon.conf .
>
> The /etc/alsa/state-daemon.conf file consists of one line:
>
>> # Remove this file to disable the alsactl daemon mode
>
> I understand that a daemon continually runs, waiting for an event and
> then acts in some way in response, but it has to mean something more in
> this context.  Anyone familiar with the internals of this?
>
>
I am not on systemd right now. I'm on CentOS 6.8. However, on an
openSUSE version I was. Sound problems were the bane of my existence
forever it seemed. So it maye take you a while to troubleshoot this.
Using JUST alsa you should be able to play sound files at the command
line. See:
http://www.alsa-project.org/main/index.php/Main_Page


I think I may have installed pulse-audio to get things working under
systemd with my GUI. What is your GUI? This may be a factor.

--
------------------------------------------
MzK

"If evolution is outlawed,
  only outlaws will evolve."

             -- Jello Biafra