Re: audio sink RuntimeError: audio_oss_sink

[aardric]

Wow. I didn't expect such a quick response; thank you all.
I noticed an option in the /etc/sysconfig/sound file:
# Load OSS-emulation modules at boot-up? (yes/no)
# OSS-emulation modules are needed if you use OSS applications
# with ALSA drivers.  This option specifies whether these modules are
# loaded at boot-time.
#
LOAD_OSS_EMUL_MODULES="yes"

For shits and giggles, I enabled it and found /dsp and /audio directories appeared after I next restarted the system.
After this, /dsp, /audio and blank work in the device field of the audio sink. The audio sink now works as well as
pulse audio (so system not broken for general use). The KDE pulse audio controls work with the audio sink although
pavucontrol& does not (audio sink reports  error: "audio_oss_sink: /dev/audio: Device or resource busy"). I don't
require pavucontrol so long as the KDE audio controls work.
Running aplay -L shows no change from before. 
So I am happy to consider this resolved and no long a diversion from other aspects of gnuradio.
Perhaps in a couple of months I will be able to contribute something useful to the project.

cheers,
Rick
> > Date: Fri, 14 Aug 2020 13:50:51 +0200
> > From: Marcus Müller <mueller@kit.edu>
> > To: <discuss-gnuradio@gnu.org>
> > Subject: Re: audio sink RuntimeError: audio_oss_sink
> > Message-ID: c1e99e0b-0146-a0b9-520f-243c9d8b2b3a@kit.edu" moz-do-not-send="true"><c1e99e0b-0146-a0b9-520f-243c9d8b2b3a@kit.edu>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Hi Rick,
> >
> > does it work when you put nothing in the device field? (because that
> > should select the default audio architecture, ALSA in your case, and use
> > the default device, which would be Pulse Audio sitting behind "default".)
> > Using "sysdefault" can normally fail, since that might not be a
> > shareable device. "default" is really what you'd normally be going for.
> > A program I like to use to see which programs use Pulseaudio, natively
> > or through the "default" ALSA device, by the way, is `pavucontrol`.
> >
> > Best regards,
> > Marcus
> >
> > On 14.08.20 00:27, aardric wrote:
> > > Hail,
> > >
> > >     I am introducing myself to SDR technology and gnuradio through
> > > whatever project documentation I find, dissecting the code and executing
> > > simple experimental flow graphs to test understanding of concepts,
> > > hoping to avoid forum queries (this is my first). Although the audio
> > > sink is not critical to my ultimate use of gnuradio and a bit of a
> > > diversion I will eventually start digging into it. However, I thought to
> > > submit a query on whether there is something obvious I should try in
> > > order to get it working. I am using gnu radio companion 3.8.1.0 (Python
> > > 3.6.10) and feeding the audio sink with a 1 kHz tone from the signal
> > > source block.
> > >
> > > (1) staring with:
> > > :~> aplay -L
> > > null
> > >      Discard all samples (playback) or generate zero samples (capture)
> > > default
> > >      Default ALSA Output (currently PulseAudio Sound Server)
> > > sysdefault:CARD=PCH
> > >      HDA Intel PCH, ALC892 Analog
> > >      Default Audio Device
> > > front:CARD=PCH,DEV=0
> > >      HDA Intel PCH, ALC892 Analog
> > >      Front speakers
> > > surround21:CARD=PCH,DEV=0
> > >      HDA Intel PCH, ALC892 Analog
> > >      2.1 Surround output to Front and Subwoofer speakers
> > > (...)
> > > hdmi:CARD=PCH,DEV=0
> > >      HDA Intel PCH, HDMI 0
> > >      HDMI Audio Output
> > > hdmi:CARD=PCH,DEV=1
> > >      HDA Intel PCH, HDMI 1
> > >      HDMI Audio Output
> > > hdmi:CARD=PCH,DEV=2
> > >      HDA Intel PCH, HDMI 2
> > >      HDMI Audio Output
> > > hdmi:CARD=PCH,DEV=3
> > >      HDA Intel PCH, HDMI 3
> > >      HDMI Audio Output
> > > hdmi:CARD=PCH,DEV=4
> > >      HDA Intel PCH, HDMI 4
> > >      HDMI Audio Output
> > >
> > > (2) using sysdefault:CARD=PCH for the audio sink device name,
> > > both 44.1 kS/s and 48 kS/s the following runtime error results:
> > >
> > > (3)
> > > gr::log :INFO: audio source - Audio sink arch: oss
> > > audio_oss_sink: sysdefault:CARD=PCH: No such file or directory
> > > Traceback (most recent call last):
> > >    File "/gnuradio/examples/audiotest.py", line 136, in <module>
> > >      main()
> > >    File "/gnuradio/examples/audiotest.py", line 112, in main
> > >      tb = top_block_cls()
> > >    File "/gnuradio/examples/audiotest.py", line 78, in __init__
> > >      self.audio_sink_0 = audio.sink(samp_rate, 'sysdefault:CARD=PCH', True)
> > >    File
> > > "/usr/local/lib64/python3.6/site-packages/gnuradio/audio/audio_swig.py",
> > > line 220, in make
> > >      return _audio_swig.sink_make(*args, **kwargs)
> > > RuntimeError: audio_oss_sink
> > >
> > >  >>> Done (return code 1)
> > >
> > > (4) Fixing this isn't critical and in time I will get to the bottom of
> > > it; the forum query just removes the possibility of an obvious answer
> > > that most everyone else knows about. My guess is that I have to disable
> > > the Pulse audio server.
> > >
> > >
> > > Rick
> > >
> > >
> > >
> > >
> > >         
> >       
>