[PlanetCCRMA] Problems startig jackd

Don Levey planetccrma@the-leveys.us
Tue May 4 13:02:01 2004

Fernando Pablo Lopez-Lezcano wrote:

> Which distro are you running? Why 2.6.x?
I'm running Fedora Core 1.  I'm on 2.6 because...  Well, in addition to the
"it's one more" than the 2.4 stream (well, two more), it's got some things
built in that I like (such as ALSA).  Also, Fedora Core 2 is coming out
soon, and will be including 2.6 as their standard core (2.6.3, I think).

> 2.6.x is not yet (AFAIK) at the same level of low latency performance
> as a patched 2.4.x kernel. There are a couple of critical patches
> that I don't think have made it to the mainline kernel yet (by
> Takashi Iwai). Also, the kernel should be built with the preemptible
> kernel option turned on, that optimizes latency a bit more but
> supposedly at the cost of stability (not all drivers are well tested
> with preempt on).
OK, I think that's the way I built it, with few stability complaints
(Evolution doesn't like to start up, but other than that I'm OK).  I will
look forward to the critical patches making their way into the mainline

> Regarding the "capabilities" complain, that is jackstart trying to get
> realtime capabilities from the kernel so that jack apps can run with
> SCHED_FIFO even as a non-root user.
> You could patch the kernel to enable capabilities, but under 2.6.x a
> better option is to use the LSM module. See:
>     http://www.joq.us/realtime/
Ah, OK - thanks!  I'm recompiling my kernel now, with the additional
security options enabled (required for the patch).

> See above...
> If you don't have a real need to be running 2.6.x you may be better
> off (for the time being) running the patched Planet CCRMA 2.4.26
> kernel...
> -- Fernando

I may set that up as yet another kernel on this box; I'll see how the LSM
module helps later tonight.  Thanks!