[PD] hdsp & pd (again..)

[julien.breval at tremplin-utc.net]

hello

I have a similar setup and finally it works

> My questions are quite simple:
> - what is the best interface to use an hdsp with ? oss, alsa, jack ?
> (when you just need to run pd and don't need to forward the audio
> elsewhere)

on my system, Pd works only with Jack

I first have to run "hdsploader" manually (and to get sound I have to 
run "hdspmixer")

Then, I start jack with the Qjackctl graphic interface

After this, the working command line for Pd is "pd -jack -rt" (the "-rt" flag 
is here to set Pd to high priority) ; you must be root to do this ("su" in a 
terminal)

If I don't use the "-rt" flag, I get lots of A/D/A sync errors (in Pd) and 
crackles when I interact with the GUIs

> - what is the typical nice setting for pd with an hdsp
> (blocksize/latency) ? what latency do you usually have ?

I use 64 or 128 samples, with 2 periods (I can't change this latter one 
actually)
Latency is 2.9 ms (64 smp) or 5.38 ms (128 smp)

> - is there any objective/obvious reasons to not use a 2.6.x kernel ?

I installed all from the PlanetCCRMA website, and there it's a special 2.4 
kernel with optimization for realtime audio / video

> - as modern computers/devices handles irqs in a more smart way now,
> would it make a "real" difference to have the hdsp set in a higher IRQ
> number?

I don't know


I hope it will help

J