manual/_manual/03_setting-up-your-system/08_platform-specifics/01_ubuntu-linux.html
2014-02-02 23:00:52 +01:00

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---
layout: default
title: Ubuntu Linux
---
<p>
Ubuntu Linux is the most popular variety of Linux in use on desktop
and laptop systems. It has the backing of a for-profit corporation
(Canonical Inc.), a defined philosophy and a huge and
worldwide user base. As a result, it is a common platform for people
who want to use Ardour and other tools for music creation and
pro-audio work.
</p>
<h2>High Level Recommendations for Ubuntu Users</h2>
<p>
Currently, installing pro audio applications on vanilla Ubuntu requires
some configuration, in order for the user to gain realtime privilege
(read below).
Ubuntu Studio, which is an official flavor of Ubuntu, and thus shares
the repositories with Ubuntu, has this already configured.
Other distributions, such as KXStudio, and Dreamstudio are largely based
on Ubuntu, and like Ubuntu Studio, has these settings preconfigured, while
also containing customized versions of Ubuntu packages, which often are
more up to date.
<p>
<h2>Installing Ardour</h2>
There may be unintended differences, and even bugs in Ubuntu native
packages, as a result of a different building method. For this reason,
Ardour developers highly recommend you to install the official
ready-to-run version of the program that you can get from <a
href="http://ardour.org/download">ardour.org</a>, as Ubuntu native
packages are not supported in official Ardour forums or other
support channels.
<h2>Problems with the interaction between PulseAudio and JACK</h2>
<dl>
<dt>Background Info</dt>
<dd>
<p>
Like many distributions, Ubuntu has decide to use PulseAudio as the
default audio system. PulseAudio is a rich and capable system that
provides excellent services for typical users of Linux on the
desktop. However, it is not capable of the type of performance that
tools like Ardour require and in particular does not offer the
possibility of sending audio between applications that can makes the
Linux audio environment a very interesting one.
</p>
<p>
This would not a problem if it were not for the fact that JACK will
not run correctly (if at all) if it needs to use the same
soundcard/audio interface that PulseAudio is using. And since on
Ubuntu, PulseAudio is configured by default to always use the
(typically single) audio interface on your computer, this is a bit
of a problem.
</p>
<p>
The developers of JACK and PulseAudio got together in 2009 and
agreed upon a mechanism by which PulseAudio and JACK could cooperate
in their use of a single soundcard. Whether or not PulseAudio is running by
default, when JACK starts up it sends out a request to use the
soundcard. If PulseAudio is running, it will give up its use of the
soundcard to allow JACK to take over (and can optionally be told to
route its own audio through JACK). When JACK finishes, it sends out
another message, and PulseAudio can once again use the soundcard
directly.
</p>
</dd>
<dt>What is the problem?</dt>
<dd>
<p>
The specific issues known at this time for all flavors of Ubuntu
12.04 and 12.10 are:
<ul>
<li>a bug in PulseAudio that causes it not to give up the
soundcard when JACK asks (<a href="https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1163638">LP: #1163638</a>
(fixed in Ubuntu 13.04).</li>
</ul>
</p>
</dd>
<dt>Symptoms</dt>
<dd>
<p>
<ul>
<li>Cannot start JACK (though see the next section for other
causes of this)</li>
</ul>
</p>
</dd>
<dt>How to fix</dt>
<p>
These bugs do not affect the upcoming 13.04 release, and earlier
releases (12.04 and 12.10) are in the process of being fixed.
</p>
<dd>
</dd>
</dl>
<h2>Problems with JACK configuration</h2>
<dl>
<dt>What is the problem?</dt>
<dd>
<p>
To function as intended, JACK needs to run with access to two
operating system facilities called "realtime scheduling" and "memory
locking". This means that you, the user who starts JACK, must be
allowed access to these facilities. By default, Ubuntu does create a
user group that has this permission but ... it does not put new
users into this group by default. Read more about why <a href="https://wiki.ubuntu.com/Audio/TheAudioGroup">here</a>.
Consequently, you will not have permission to run JACK in the way you should.
</p>
</dd>
<dt>Symptoms</dt>
<dd>
<p>
A message like "Cannot lock down memory" in the output from JACK as
it starts up. This output may be "hidden" in the Messages window of
QJackctrl (aka JACK Control), so you should check there.
</p>
</dd>
<dt>How to fix</dt>
<dd>
<p>
Make sure the file /etc/security/limits.d/audio.conf exists. If it is
named /etc/security/limits.d/audio.conf.disabled, rename it to the former.
Run the command <code>sudo usermod -a -G
audio <em>YOUR-LOGIN-NAME</em></code>. Then logout and login again.
On Ubuntu Studio the user is a member of audio group by default, but not
on other official flavors.
</p>
</dd>
</dl>
<h2>Reporting Issues</h2>
<p>Given the difficulties in supporting Ubuntu and the limited time/resources of the Ardour team, the <code>Ubuntu Studio Project</code> has requested that issues and bug reports related to Ubuntu, Ubuntu Studio and other derivitives be directed to them.</p>
<h4>Contact Information for Ubuntu Studio</h4>
<p><a href="http://ubuntustudio.org" target="_blank">The Ubuntu Studio Homepage</a></p>
<p><a href="http://ubuntuforums.org/forumdisplay.php?f=335" target="_blank">The Ubuntu Studio Forums.</a></p>
<p><a href="https://help.ubuntu.com/community/UbuntuStudio/MailLists" target="_blank">Information on the Ubuntu Studio Mailing Lists.</a></p>
<p><a href="https://help.ubuntu.com/community/UbuntuStudio/IRC" target="_blank">Information on the Ubuntu Studio IRC channel.</a> #ubuntustudio on irc.freenode.net</p>