[Ubuntu Studio] Release Meeting 2012-01-27

[Steve Langasek]

On Fri, Jan 27, 2012 at 06:57:49AM -0600, Scott Lavender wrote:

> > Can you please expand on this a little? We usually assign device
> > permissions dynamically through ConsoleKit/PolicyKit these days.

> > We can easily put the "ubuntu" user into the audio group in casper,
> > but I wouldn't like to do this for users created in the actual
> > install. This problem sounds like something that doesn't only affect
> > the live system?

> thank you for asking, martin.

> the use of the 'audio' group is a method to grant improved real time
> priority to help reduce latency for audio work (the -lowlatency kernel
> is another pursuit of the same goal).

> when jackd is installed, it creates /etc/security/limits.d/audio.conf,
> in which is:

>      @audio   -  rtprio     95
>      @audio   -  memlock    unlimited

> during installation, the created user will then be added to the 'audio' group.

> setting memlock to 'unlimited' has admitted potential for denying
> memory for a second user logged into the system.  however, ubuntu
> studio is considered to be mainly a single user case, and given the
> large size of some synth sample libraries available, it was weighed
> and decided to follow this path.

Right; both of these are settings that are not appropriate defaults for
non-UbuntuStudio installs, and there's no other reason for the default user
to be in the audio group nowadays.  If there's a way for an image to
special-case additional groups to put the default user in, that's probably
the best way forward IMHO.

(BTW, although it doesn't help with the memlock question, could RtKit be
used here to make the rtprio limit irrelevant?)

-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek at ubuntu.com                                     vorlon at debian.org
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