[PlanetCCRMA] how to determine hw:0 is already in use issue

Len lenb_99@yahoo.com
Fri May 25 11:57:00 2007

 On 5/25/07, Tom Poe <tompoe@fngi.net> wrote:
 > jackd 0.101.1
 > Copyright 2001-2005 Paul Davis and others.
 > jackd comes with ABSOLUTELY NO WARRANTY
 > This is free software, and you are welcome to redistribute it
 > under certain conditions; see the file COPYING for details
 > JACK compiled with System V SHM support.
 > 11:51:04.106 MIDI connection change.
 > loading driver ..
 > apparent rate = 48000
 > creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
 > control device hw:0
 > the playback device "hw:0" is already in use. Please stop the
 > application using it and run JACK again
 > cannot load driver module alsa
 > 11:51:04.141 JACK was stopped successfully.
 > 11:51:06.121 Could not connect to JACK server as client. Please check
 > the messages window for more info.
 > - - -
 > How do I determine what device is already in use.  I'm running FC5 with
 > planetccrma kernel.  I removed all spaces from /etc/modprobe.conf,
 > checked:
 > ]# cat /proc/asound/cards
 > 0 [I82801AAICH    ]: ICH - Intel 82801AA-ICH
 >                       Intel 82801AA-ICH with AD1881 at 0xd800, irq 10
 > [root@localhost bin]# cat /proc/asound/devices
 >   0: [ 0]   : control
 >   1:        : sequencer
 > 16: [ 0- 0]: digital audio playback
 > 24: [ 0- 0]: digital audio capture
 > 25: [ 0- 1]: digital audio capture
 > 33:        : timer
 > - - -
 > I shut down computer, then started computer, have the sound volume
 > center thingy on the desktop working, so sound is coming from oss?
 > alsa?  But, when I try to start qjackctl, the above message appears.
 > Tom


I think your problem might be the "sound volume center thingy on the desktop".  If you have a
volume control app using the playback device hw:0, then jack will not be able to connect to the
device because it is already in use.  You need to close any app that is connected to oss/alsa, and
disable any audio app that starts up by default when you log into Gnome/KDE (like the volume
control app).  You may already know this, but alsa (or oss, artsd, etc) only allows one connection
at a time.  This is where Jack comes in:  Jack is able to act as a go-between with the sound
server and other audio apps.  It makes that single connection to the sound server, but then makes
multiple connections available for other audio apps to connect to Jack.  Without Jack you would
only be able to run one audio application at a time.

Hope this helps,

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