What's wrong with jack ?

Hartmut Noack zettberlin at linuxuse.de
Tue Jun 1 14:11:00 BST 2010

Am 01.06.2010 14:08, schrieb Pablo Fernandez:

> I find it neater the way it is now. As a user, I think the case
> is similar to /etc/apt/sources.list and
> /etc/apt/sources.list.d/someother.list
> Particular configurations for particular goals are in a separate file.
> Someone in the LAU list mentioned other examples and gave better reasons.
> Anyway,  the user does not have to bother anymore with editing a system
> file.
> More authoritative reasons are here:
>   http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=507248

Very interesting read - thanks for the link!

This discussion shows quite clearly, where the overall problem with 
pro-audio on Linux lies: Those, who do the good work in building Distros 
like Debian do not know about pro-audio. If you tell them, that it is so 
demanding, they see a risk for their overall working system/security 
etc. And they are apalled to hear, that there are some crazy people out 
there, that want to have a 970MB-File locked into memory to be 
accessible with less then 10ms latency.

This I understand but I do absolutely not understand, that these 
tech-people do not react like this:

"Well quite interesting stuff, you crazies do there - let us do whatever 
possible and sane to make our system support such incredible features!"

They act more like:

"Comeon, do not bother us with such strange single-user 
niche-applications. Do this if you like but stay away from our great 
system settings that work so well for dozens of years now."

> I like when Steve writes "common doesn't mean correct".

I am not sure if he really knows, what he is talking about.

The whole thing is, that jack, though it is a user-process, needs to be 
priviledged even more than the avarage root-process in order to work 
properly for the user. And this is not a bug or a flaw in the design of 
jack but simply a neccissity. This process needs to access data as fast 
as technically possible. Can the kernel-memory management guarranty 
that? Apparantly not. So you have 2 decisons:

1.) have a system set up conservatively for everyone, that runs normal 
Desktop-Apps and thats it. No RT-apps on Linux at least not for users 
with higher skills in tweaking system settings.

2.) find a sane way to let the user decide, what he/she likes to do with 
the system-setup.

> We will have to learn again  :)

Everybody needs to learn every day.

>> Plus, as you mention yourself later on, the script must set up group
>> audio as well, this is a no-brainer and I really do not know, why the
>> packagers do not implement that.
> I didn't say exactly so. I think a package script must not deal with users
> and groups.
> But the distro should do it, imho.

You mean: group audio should be set up in the initial install and the 
first user should be in that group?

>>> For the rest, qjackctl launches pasuspender so pulseaudio is (almost) out
>> of
>>> the way.
>> I recommend that. It works very much OK for me.
>>> Afaik, a cleaner approach than pasuspender or the rm you suggest in
>> getting
>>> rid of pulseaudio is the following:
>>> qjackctl -->   Options tab, execute script on startup:
>>> pulseaudio -k
>>> (this kills pulseaudio) (artsshell sounds like jurasic)
>>> However, pulseaudio will respawn automatically if you don't do the
>>> following:
>>> $ sudo edit /etc/pulse/client.conf
>>> Change the line:
>>> ; autospawn = yes
>>> to:
>>> autospawn = no
>>> If you wish to start pulseaudio, once the jack session is finished:
>>> $ pulseaudio --start
>> This methods I tried in Open Suse 11.2 and it broke my system so
>> globally and totally that I abandoned the OpenSuse-Installation. So I
>> really recommend to check out, if pasuspender does the trick
> In my case, pasuspender does the trick but I don't want a pulseaudio daemon
> running at all.
> https://help.ubuntu.com/community/UbuntuStudioPreparation#Pulse%20Audio
> recommends creating a *~/.pulse/client.conf*  with "autospawn = no" (instead
> of editing the system wide /etc/pulse/client.conf as I suggested) and then
> put "pulseaudio -k" as a "Startup Application".

The latter looks promising. If I find the time, Ill try it just for 
curiosity ;-)

best regs


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