From 28f75f8ad563c8aaf7b56aa1a67675028ad80ff6 Mon Sep 17 00:00:00 2001
From: Paul Davis
- 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.) behind it, 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.
-
- Unfortunately, Ubuntu has repeatedly caused major headaches for
- people who want to use Ardour. These problems have arisen from a
- combination of two basic issues:
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- Ubuntu Linux
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- It is not possible to know whether the current package of Ardour - released by Ubuntu has been correctly built or not. Ubuntu has a - history of making packaging errors that lead to crashes, missing - functionality and odd behaviour that is not present in the - ready-to-run version of the program that you can get from ardour.org - (or in the packages released by other distributions) -
- If you plan to use Ardour on Ubuntu, you are strongly - recommended to download the ready-to-run version from - ardour.org. Ardour's lead developer (and many of the most active - members of our user community) will not provide support for, and - will not investigate bugs reported for, Ubuntu's own packages of - Ardour. -
-- If have already installed the Ubuntu package of Ardour and find that - although the program starts up and basically runs, but you are - running into more subtle problems (for example, with plugin GUIs or - with export, or with the use of certain specific plugins), then you - are strongly recommended to download the - ready-to-run version from ardour.org. -
- -- 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. -
-- 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. -
-- 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. -
-- This relatively simple system ought to be the basis for excellent - cooperation between PulseAudio and JACK. Unfortunately, it relies on - everything being correctly configured for it to work, and Ubuntu - have repeatedly failed to get this configuration correct. -
- -- The specific issues known at this time (spring 2013) are: -
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- 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. Consequently, you will not have - permission to run JACK in the way you should. -
- -- 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. -
- -
- Run the command sudo usermod -a -G
- audio YOUR-LOGIN-NAME
. Then logout and login again.
-