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

Tim Janes twjanes at gmail.com
Wed Feb 28 23:10:47 CET 2018


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 <twjanes at gmail.com> 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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