[Mageia-dev] mageia sound tasks

Fri Dec 17 17:49:02 CET 2010

After having a looong chat with the guys from linux4audio and reading tons
+of posts in ccrma forum, I must say .....
+
+Idea with an rt-kernel for netbooks ....... DISMISSED .... it simply makes
+no sense.
+Those guys mostly use gentoo and build their own kernel for years now and
+they gave me the following hints, that also can be found in discussions of
+other distributions:
+1) the kernel (without preemption-patch) should have
+
+Processor type and features >> Preemption Mode >> Complete Preemption
+(Real-Time)
+Processor type and features >> Timer frequency >> 1000 HZ
+General setup >> RCU Subsystem >> RCU Implementation (Preemptable
+tree-based hierarchical RCU)
+
+ Proccesor Type and features >> Tickless System (Dynamic Ticks) should be
+excluded
+
+
+Idea with multiple tasks .... DISMISSED ...... one task that installs
+drivers likje ffado and stuff like Jackit and sessionhandling and .... the
+other little stuff one needs, is a really good Idea.
+(a big discussion should be held here on wich would be the best tools)
+The rest, like LADSPA, DSSI, Soundfonts or apps like ardour, lmms ......
+should not be included, it's simply too much.
+
+We could provide a script that adds the content we need, like:
+1) alter /etc/security/limits.conf
+@audio - rtprio 99
+@audio - memlock unlimited
+
+2) add to /etc/rc.d/rc.local
+echo 2048 >/sys/class/rtc/rtc0/max_user_freq
+echo 2048 >/proc/sys/dev/hpet/max-user-freq
+
+maybe add 2 new files to /lib/udev/rules.d
+a) 40-rtc-permissions.rules with: KERNEL=="rtc0", GROUP="audio"
+b) 40-hpet-permissions.rule with: KERNEL=="hpet", GROUP="audio"
+
+On fedora ccrma, audio4linux and other forums, the musicians eaven do not
+use the RT-Kernel anymore since 2.6.33.
+They report that it works better without the Preemption RT Patch with the
+stuff above and they get a really low latency (~ 2 ms) mit an old M-Audio
+2496 without Jack XRUNS.
+
+I tested these hints (exept compiling a kernel) today and it really works
+much better.
+I could reduce the latency on my laptop with build in soundcard from 23.2ms
+to 5.8ms (44100 kHz)
+
+
+2010/12/17 Romain d'Alverny <rdalverny at gmail.com>
+
+> On Fri, Dec 17, 2010 at 13:27, Michael Scherer <misc at zarb.org> wrote:
+> > Le vendredi 17 décembre 2010 à 12:35 +0100, Sascha Schneider a écrit :
+> >> [...]
+> >> Work to be done:
+> >> - provide sound packages like hydrogen, ardour, jackit ......
+> >> - provide TWO good realtimekernel, one for desktop and another for
+> netbooks
+> >
+> > Given the fact that each kernel add a certain load on hdlists, I think
+> > we should really try to avoid their proliferation.
+> > ( kernel represent 33% of the size of contribs hdlist at Mandriva ).
+>
+> This is not necessarily proliferation if it has a legitimate purpose
+> for the user needs. Maybe this could be merged with other existing rt
+> kernels.
+>
+> If that makes for a really big issue for the final repository index
+> files in the end, then it may be a good reason to have a music studio
+> derivative distribution. Or find another solution?
+>
+> you are right, too many kernels is not what makes it better.
+
+
+> >> - provide a script or someting like that, that scanns and adds sound
+> >> specific stuff to the limits.conf, /etc/udev/rules.d and
+> /etc/rc.d/rc.local
+> >> and other places
+> >> - provide tasks files that really only install good and necessary sound
+> >> stuff.
+> >
+> > Good luck with deciding what is "good and necessary". You will always
+> > end frustrating people whose definition of good and necessary to be
+> > different.
+>
+> Nothing will ever please everyone. But it's good to have a
+> recommandation/selection of whatever works best/best fits some
+> purpose, to avoid having to test everything everytime to have a
+> working setup; here a music studio.
+>
+
+This might be an idea, to simply provide an iso containing the basic setup
+like above with LXDE that uses the standard mageia repos for installation
+and updates.
+
+
+> So this may not be the best way to put it (using a rpm task), but it
+> looks like it. Having a basic recommendation set for a particular
+> purpose, on top of all available software in the distribution, does
+> not sound bad to me (further than that, having a way to
+> customize/store/retrieve this set).
+>
+> Althought trying new stuff is great too, there are times you prefer to
+> focus on production and just install/restore tools that just works,
+> without taking too much time in this.
+>
+> (we're not to the point of having something like a allmyapps.com
+> equivalent though).
+>
+> > And secondary, I think we should also try to avoid having too much task-
+> > rpms. Their values is in the fact they allow to quickly install a set of
+> > rpm without searching in the whole set of rpm.
+>
+> Indeed.
+>
+>
+> Romain
+>
+greetings, Sascha
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