[pulseaudio-discuss] alsa-util.c: Unable to attach to mixer

[Lennart Poettering]

On Thu, 31.07.08 09:19, Ben Finney (bignose+hates-spam at benfinney.id.au) wrote:

> > > I: core-util.c: Successfully gained nice level -11.
> > > W: main.c: This program is not intended to be run as root (unless
> > > --system is specified).
> > 
> > Don't run PA as root!
> 
> The daemon is to be started as a system service on startup, since no
> users will be logging in; see earlier in the thread for why (summary:
> this is a networked host with the desired audio devices, which is one
> reason PulseAudio is attractive).

If you do this, then specify --system.

> > > ALSA lib control.c:909:(snd_ctl_open_noupdate) Invalid CTL plug:hw:0
> > > I: alsa-util.c: Unable to attach to mixer plug:hw:0: No such file or directory
> 
> Is this not indicative that PA is still having trouble connecting to
> 'plug:hw:0'?

Yes, for the mixer ('ctl'). "plug" doesn't implement a ctl interface.

> 
> > > I: alsa-util.c: Unable to attach to mixer hw:(null): No such device
> > > I: sink.c: Created sink 0 "output" with sample spec "s16be 2ch 44100Hz"
> > > I: source.c: Created source 0 "output.monitor" with sample spec "s16be 2ch 44100Hz"
> > > I: module-alsa-sink.c: Using 4 fragments of size 4408 bytes.
> > > D: module-alsa-sink.c: Thread starting up
> > > D: rtpoll.c: Acquired POSIX realtime signal SIGRTMIN+29
> > > I: module-alsa-sink.c: Starting playback.
> > > I: module.c: Loaded "module-alsa-sink" (index: #0; argument: "device=plug:hw:0 sink_name=output").
> 
> This indicates PA thinks it *can* talk to 'plug:hw:0'. Which
> interpretation is right?

Yes, for PCM. "plug" implements pcm just fine.

> =====
> .ifexists module-hal-detect.so
> load-module module-hal-detect
> .else
> load-module module-detect
> .endif
> =====
> 
> Since the output shows 'module-hal-detect.so' exists, this should mean
> the 'load-module module-detect' will not occur. Is that right?

Yes. And?

> Testing the client (via GNOME's "Preferences -> Sound -> Devices ->
> Music and Movies -> Test") cycles without anything audible, until I
> stop it.

This really looks like an alsa mixer problem. Please play around with
all controls you find in "alsamixer -c0"!

> > Are you sure your stream is connected to the right device?
> 
> How can I tell? What should I try to test this?

Try "pavucontrol" and right click on the stream and choose the right device.


Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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