[PlanetCCRMA] Problem with qjackctl in Fedora 14

[Fernando Lopez-Lezcano]

On 12/30/2010 09:59 AM, Orcan Ogetbil wrote:
> Hello all,
>
> Sorry I have been busy lately with real life and my upstream projects,
> and I didn't spend much time on packaging lately (except I built the
> new qjackctl-0.3.7 recently). I hope you figured things out by now.
>
> On Thu, Dec 30, 2010 at 7:15 AM, Oded Ben-Tal wrote:
>>> You can add this file (name it "90-jack.conf") to the
>>> /etc/security/limits.d/:
>>>
>>> ---- CUT HERE
>>> # Planet CCRMA, jack-audio-connection-kit
>>> #
>>> # Allow processes access to rt priority and memory locking
>>> # without limits, needed by the rt kernel and jackd
>>> *     -       rtprio  99
>>> *     -       memlock 4194304
>>
>> Possibly silly questions. Perhaps because I upgraded from an earlier
>> version I have two files in /etc/security/limits.d/
>> 90-nproc.conf  99-jack.con
>>
>
> Typo? It should be 99-jack.conf. Otherwise pam won't read it.
>
>> questions:
>> 1) do the number matter (i.e. is it important that the jack one is 90)?
>>
>
> The documentation says: "The files are parsed one after another in the
> order of "C" locale."
>
> That means 99 beats 90. Unfortunately, I did set the conf file that
> comes with jack to 99. I was probably assuming the other way around.
> Should I pull that number down in the jack package so the
> corresponding PlanetCCRMA package can override?

It would be nice to have that option, 99 precludes anyone else from 
changing the priority (I had not noticed that).

> Of course, you can
> give RT priorities to all users, then 99-jack.conf file won't do
> anything. But this would be insecure, right?

Yes, it would open the door to denial of service attacks, for example. 
But for a "normal" audio workstation with trusted users that would be of 
little consequence (others surely will disagree).

I have to see what I can do to change things in the rt patched kernel 
and rtirq so that it is possible to use it with the reduced (arbitrary) 
priority of 20.

-- Fernando


>> 2) This is what I have in 99-jack.conf
>> @jackuser - rtprio 99
>> @jackuser - memlock 4194304
>> @jackuser - nice -10
>>
>> @pulse-rt - rtprio 20
>> @pulse-rt - nice -20
>>
>> I presume that since I am a member of the jackuser group rhat should work,
>> right?
>>
>
> Correct.
>
> A note to the other people who are reading this email: The
> 99-jack.conf file that comes with Fedora has @jackuser - rtprio 20.
> Oded modified it to @jackuser - rtprio 99 which is necessary for the
> RT kernel use.