The audio group

[David Henningsson]

2010-08-24 15:56, ttoine at ttoine.net skrev:
> 
> 
> Le 24/08/2010 12:11, Cory K. a écrit :
>> On 08/24/2010 04:56 AM, David Henningsson wrote:
>>   
>>> Hi,
>>>
>>> Adding users to the audio group is not recommended for reasons I've just
>>> documented here: https://wiki.ubuntu.com/Audio/TheAudioGroup
>>>
>>> Looking at ubuntu studio documentation, you seem to recommend people to
>>> add themselves to the audio group pretty much (found by doing a search
>>> for "audio group" on help.ubuntu.com), so can we remove it? Change it to
>>> something else?
>>>
>>>      
>> That's under the "community" section. Something we don't control.

Or rather, we control it as much as anyone else in the community.

>>
>> Also, it was nessesary in the past because of permissions needed for
>> some soundcards. (firewire I believe) From what I have seen, our users
>> are folks who have "single-user" systems. (this is actually our target
>> audience and setup) So your "Implications" section will not apply to
>> them.
>>
>> Someone with more current grasp on the situation should chime in. As
>> long as a solution can be found that works for everyone we can change
>> the documentation. In the end, adding users still might be needed for
>> corner cases and those folks won't care. They'll just want their gear to
>> work. :)
>>
>>
>> -Cory K.
>>
>>    
> David, Cory,
> 
> Their would be one case, when a user would have his workstation in a
> dedicated room for noisy hardware, and use a remote connection with a
> low power computer in the studio, where this could be a problem as David
> described.

Right, noted.

> With the current LTS release, the use of the "audio" group is for a real
> time use of jackd. The document you may have found is this one, I guess:
> https://help.ubuntu.com/community/UbuntuStudioPreparation#Real time
> (-rt) and Low latency (-lowlatency) kernels
> <https://help.ubuntu.com/community/UbuntuStudioPreparation#Real%20time%20%28-rt%29%20and%20Low%20latency%20%28-lowlatency%29%20kernels>

And a few more, yes.

> For firewire sound cards, ffado driver needs user to be member of the
> "video" group, as a firewire sound card is considered to be similar as a
> "dv" camera by firewire libraries.

Slightly off topic, does this apply to the new fw stack in maverick as
well, or are fw devices handled by ConsoleKit? (Note to myself: I should
really upgrade to maverick and test that, soon.)

> Maybe, we just have to change "audio" group for "realtime" or something
> like that. 

Seems reasonable. In addition, a few months ago, I made a client unit
for requesting real-time privileges through realtimekit (for
FluidSynth), and while this does not give out anything above rtprio ~20
(or was it 30) by default, I think it would be a valuable addition to jackd.

Reference:
http://fluidsynth.svn.sourceforge.net/viewvc/fluidsynth/trunk/fluidsynth/src/bindings/fluid_rtkit.c
http://fluidsynth.svn.sourceforge.net/viewvc/fluidsynth/trunk/fluidsynth/src/bindings/fluid_rtkit.h

> That would mean changing the post configuration of jackd
> installation package, wich create the "audio" settings/entries for real
> time use. If you think this is compulsory, then, it is easy to do it:
> ask the jackd maintainer to change the group name, I and other update
> their documentation and it's done.

Are you talking about Debian's pkg-multimedia-maintainers, or the jack2
upstream developers at jackaudio.org?

> To "fine tune", a dedicated possibility should be added to "User and
> Group Manager Privileges" GUI, and maybe the "Use audio devices" should
> be renamed for "Use audio devices on remote connection" or something
> like that.

True, I've already suggested that but it seems stuck in bureaucracy:
https://bugs.launchpad.net/bugs/616998

-- 
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic