Preface: I am running Hammerfall hdsp multiface on a dell i8000, using FC2t1 and the standard 2.6.4 kernel

• what is the best interface to use an hdsp with ? oss, alsa, jack ?
• what is the typical nice setting for pd with an hdsp

(blocksize/latency) ? what latency do you usually have ?

IO is right, there is no real way to run the hdsp on oss, though oss emulation as done via the kernel seems to work fine for me. Alsa, and jack on top of alsa works for me. The jack I run is this, for pd: sudo jackd -d alsa -d hw:1 -r 48000 -p 256 Which should give me a 256/48000 sec buffer of latency (approx 5msec). Takashi's latency testing module says that my machine can go to 3.9 msec latency http://www.aproximation.net/test1/

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

No. the 2.6.x kernel works better for me, though I have heard some people complain of larger latency. I have no such problems. If anything my latency went DOWN, though I wasnt using any of the super-duper kernel patches for 2.4.x...

• 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?

Im not sure about what your talking about here, but I have seen some texts about modifying irq's to reduce latency. Ive had to do no such thing.

The hdsp worked "out of the box" for me, after some attempts at configuring the kernel correctly. the .asoundrc and esd.conf file helps a lot too, for standard apps like mozilla and xmms (though xmms worked in oss emulation too). I didnt get the xmms-jack plugin to work though. It would be nice to listen to xmms while coding pd...

Hope this helps! -thewade