[Jack-Devel] The playback device hw:0 is already in use

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[Jack-Devel] The playback device hw:0 is already in use

Tim Janes
I am new to jack and trying to setup Jack2 on Ubuntu 17.10 on a Dell
laptop 15-5570 that uses a Realtek ALC3246 sound device.

It is basically working ( I am testing it with simple_client and
latent_client) but I think that I am doing something wrong as the first
time I use it after booting the laptop  I get the error.

"ATTENTION: The playback device "hw:0" is already in use. Please stop
the application using it and run JACK again"  followed by lots of

"Cannot connect to server socket err = No such file or directory"
"Cannot connect to server request channel"

fuser -v /dev/snd/pcmC0D0p shows that it is use by pulseaudio.

However the 2nd and subsequent runs of the jack example clients work
just fine without any error.

Thanks for any suggestions or help

Tim.

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Re: The playback device hw:0 is already in use

David Kastrup
Tim Janes <[hidden email]> writes:

> I am new to jack and trying to setup Jack2 on Ubuntu 17.10 on a Dell
> laptop 15-5570 that uses a Realtek ALC3246 sound device.
>
> It is basically working ( I am testing it with simple_client and
> latent_client) but I think that I am doing something wrong as the
> first time I use it after booting the laptop  I get the error.
>
> "ATTENTION: The playback device "hw:0" is already in use. Please stop
> the application using it and run JACK again"  followed by lots of
>
> "Cannot connect to server socket err = No such file or directory"
> "Cannot connect to server request channel"
>
> fuser -v /dev/snd/pcmC0D0p shows that it is use by pulseaudio.

Well, tell Pulseaudio to stop hogging the device.  One way is to call
pavucontrol and turn that device's Pulseaudio profile to "Off".  Another
is to configure Pulseaudio to not restart in the first place (create a
.pulse/client.conf file containing

autospawn = no

.  You will then need to start pulseaudio manually using

pulseaudio -D

every time you want to use it.  One audio daemon less competing for
realtime resources is probably not the worst idea, but I don't really
know how much of a problem a dormant Pulseaudio can be.



--
David Kastrup
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Re: The playback device hw:0 is already in use

Tim Janes
Thanks David,

I tried as you suggest, but then I loose the volume control in the
system tray and the volume functions keys don't work, so I loose all
control of the volume - so it is not an option.

It all seems very intermittent, sometime I get the device in use, other
times I get no such device (as below) and others it works.

creating alsa driver ... hw:0|hw:0|256|2|8000|0|0|nomon|swmeter|-|32bit
control open "hw:0" (No such file or directory)
ALSA lib pcm_hw.c:1713:(_snd_pcm_hw_open) Invalid value for card
ALSA lib pcm_hw.c:1713:(_snd_pcm_hw_open) Invalid value for card
ALSA: Cannot open PCM device alsa_pcm for playback. Falling back to
capture-only mode
Cannot initialize driver
JackServer::Open failed with -1

My workaround for now is to start  jackd manually and repeat until it
works. Occasionally it works 1st time, usually 2nd and occasionally it
takes 3 times. It also fits in with my requirement of needing to use it
at 8kHz.

If jack becomes a permanent feature then I will have to revisit this but
for now its satisfactory.

My manual startup script is as below (the non jackd commands are just to
try and get a clue to the problem)

fuser -v /dev/snd/pcmC0D0p
nohup jackd -d alsa -r 8000 -p 256 &> /tmp/jackd.log &
sleep 2
fuser -v /dev/snd/pcmC0D0p
ps aux |grep jackd | grep -v grep

I am struggling as I have yet to locate any documentation - Can anyone
give me a link?

Thanks for your help

Tim


On 27/02/18 22:37, David Kastrup wrote:

> Tim Janes <[hidden email]> writes:
>
>> I am new to jack and trying to setup Jack2 on Ubuntu 17.10 on a Dell
>> laptop 15-5570 that uses a Realtek ALC3246 sound device.
>>
>> It is basically working ( I am testing it with simple_client and
>> latent_client) but I think that I am doing something wrong as the
>> first time I use it after booting the laptop  I get the error.
>>
>> "ATTENTION: The playback device "hw:0" is already in use. Please stop
>> the application using it and run JACK again"  followed by lots of
>>
>> "Cannot connect to server socket err = No such file or directory"
>> "Cannot connect to server request channel"
>>
>> fuser -v /dev/snd/pcmC0D0p shows that it is use by pulseaudio.
> Well, tell Pulseaudio to stop hogging the device.  One way is to call
> pavucontrol and turn that device's Pulseaudio profile to "Off".  Another
> is to configure Pulseaudio to not restart in the first place (create a
> .pulse/client.conf file containing
>
> autospawn = no
>
> .  You will then need to start pulseaudio manually using
>
> pulseaudio -D
>
> every time you want to use it.  One audio daemon less competing for
> realtime resources is probably not the worst idea, but I don't really
> know how much of a problem a dormant Pulseaudio can be.
>
>
>

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Re: The playback device hw:0 is already in use

Bengt Gördén-3
Den 2018-02-28 kl. 23:10, skrev Tim Janes:
>
> I am struggling as I have yet to locate any documentation - Can anyone
> give me a link?

This sounds very much like an old ubuntu/pulseaudio-bug. Is it a fresh
17.10 or upgraded? It actually sounds more like an ubuntu problem than a
jack problem.

https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1163638

I run ubuntustudio 17.10 and it doesn't have this kind of problem. You
might want to check it out.

https://ubuntustudio.org



--
/bengan

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