Re: [Jack-Devel] xruns on NVidia HMDI output

On September 22, 2011 06:31:06 pm Joshua N Pritikin wrote:
> Greetings!
>
> I am trying to get a very basic setup working. I would like to use jack
> in output-only mode. I only want to use a MIDI keyboard with a MIDI
> sequencer and something like zynaddsubfx. I don't care too much about
> audio latency. Simple, right?
>
> Here is my set up:
>
> Ubuntu 11.04 SMP 2.6.38-11-generic x86_64
> jackd2 1.9.6~dfsg.1-5ubuntu1
> 10de:0be3 nVidia Corporation High Definition Audio Controller
>
> This output device drives the audio on the HDMI cable. It only has
> SP/DIF outputs.
>
> I am using pasuspender to finesse pulseaudio issues. I have jackd2
> running with real-time scheduling and locking memory. The machine has no
> other load. Two periods gives me tons of xruns. If I use 3 periods
> (helpful for snd-hda-intel?) then I don't get any xruns until I try to
> start a jack client. Any jack client (e.g. jack_metro) will cause lots
> of xruns. My HD TV outputs jack audio and it doesn't sound too bad, but
> I bet it would sound better if I could eliminate the xruns.
>
> What more information can I provide? Is there some trick to getting this
> to work?
>
> Thanks!

Hello, not a Jack devel here, but just curious, and maybe can help here:
I just finished completely migrating my programming and music production
 over to a (K)Ubuntu 11.04 box.

You say you've got locking memory working...
Does this mean you added some lines in the /etc/security limits files?
Or, do you see a file /etc/security/limits.d/audio.conf with the correct 
 settings?
Note: If the filename is "audio.conf.disabled", change it to "audio.conf"
And did you add yourself (user) to the audio group?

I'm not sure how well these changes work with the stock generic kernel.
Because the first thing I did was install the "linux-lowlatency" kernel 3.0.xx
 available only in one of the ppa archives. 
You might want to try that. (Here on this KUbuntu I also had to install a 
 certain kde settings package to allow the grub boot manager settings to 
 be changed to show multi-boot menus, so I can 'fall back' to another kernel
 in case things don't work.)
They say to try the generic kernel first and if that's not satisfactory, then 
 try the lowlatency kernel.
  
I'm happy to report that our project, MusE, works flawlessly. No xruns. 
Especially now that I know how to use Jack's -S (synchronous) setting.
You can try that setting if you get a lot of xruns or "jack activation count"
 errors.

Tim.

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