JACK's behavior revealed another problem

hollunder at gmx.at hollunder at gmx.at
Mon Nov 10 13:32:46 GMT 2008

On Sun, 09 Nov 2008 14:56:24 +0100
Tomas Valusek <tvalusek at gmail.com> wrote:

> Hello,
> thank you for your help with JACK. I have cought very basic grip of
> it, and stumbled upon another problem. I'm using proprietary ATI
> drivers, since with them work cltr-alt-grayplus and
> ctrl-alt-greyminus to change screen resolution while maintaining a
> desktop size, thus providing mi with very useful, although very
> basic, magnifier. But now when system starts, sound devices are given
> their system names randomly - sometimes is hw:0 assigned to SB Audigy
> and hw:2 to HDA ATI HDMI, sometimes is HW:0 ATI and hw:2 Audigy. I
> have not recognized the way hw:* devices are assigned, but when JACK
> stumbles upon ATI, it refuses to start. So every time I see JACK's
> error message, I have to enter setup window and re-select input and
> output devices.
> And BTW, latency displayed by the Setup dialog is 46.4 msec :(
> Tomas Valusek
> PS: Here is my current contents of .jackdrc file:
> /usr/bin/jackd -dalsa -r44100 -p1024 -n2 -D -Chw:0 -Phw:0

This is how I solve this: open a console and type: 'aplay -l'

you should then get a list of audio devices. In my case the relevant
device is:

card 1: UA25 [UA-25], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Then open qjackctl's setup dialogue and enter the following in the
interface field: 'hw:UA25'
The relevant name in this case is UA25 which comes up just after 'card

If you do this jack is hardwired to the device name, not a possibly
changing number.
If you have more devices with the same name there are other options but
this one is simpler and is enough in many cases.

Best regards,

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