ALSA in a 2.6 world

[Florin Andrei]

On Fri, 2004-04-16 at 10:49, Fernando Pablo Lopez-Lezcano wrote:

> There are a couple more issues that pertain to doing "professional"
> audio under 2.6.x that are not addressed by the current Fedora Core
> kernel builds, AFAIK
> If you are concerned about latency (ie: using very small audio buffers)
> then the stock configuration of the 2.6.x kernel has the preemptible
> kernel option turned off. In my tests latency is worse than with it
> on[1]. 

That's a showstopper for doing serious MIDI and DAW stuff. Preempt must
be turned on for any kind of serious work in that field.

So, the stock 2.6 has it turned off. How about the FC2 pre-releases? Do
they also turn it off?

> If you want to use the Jack low latency audio server (Jack Audio
> Connection Kit) with realtime privileges (SCHED_FIFO) then the obvious
> alternative is to build and load the LSM kernel module[2]. Regretfully
> that would need CONFIG_SECURITY_CAPABILITIES to be a module instead of
> being built into the kernel, as in the last build I tried (otherwise you
> can't build the LSM module). 

If i run JACK as root, do i still need the LSM module?

Currently i run all the audio/MIDI stuff as root, since security is not
an issue on that system, and this way i don't ever see any of the
privilege issues that normally come up.
It's not elegant, though, i admit it.

-- 
Florin Andrei

http://florin.myip.org/