[LAU] Hardware latency of firewire controller

[Pieter Palmers]

Ismael Valladolid Torres wrote:
> My colleague bought a Presonus FP10 firewire audio interface, which
> reports working nice in Linux. Moreover he owns a firewire controller
> made by Sunix with a Texas Instruments chipset. He tells us that for
> having jackd working without xrun and no other artifacts he needs to
> use 512 frame/periods, then latency is 34ms, which could be considered
> awful as this card is able to work with 2ms latency using other
> operating systems.

Rereading your mail regarding to check what device we're talking about, 
I can't resist to comment on this. Please don't compare Linux latency 
figures with those of other operating systems. At least not if you 
didn't actually measure the latency. It's not because there is a setting 
that says "2ms" that this is the latency you get. Not at all. Usually 
there is a ASIO latency of e.g. 2ms/buffer times 2 buffers, then another 
2ms ISO buffering at each side. The end result is that for a 'setting' 
of 2ms you have 10ms in reality.

The numbers displayed in Linux are marketing-free, hence try to provide 
a real number.

34ms is still too much though, that's for sure. Just don't buy the 2ms. 
I know it's not true if you measure it the way we do.

Greets,

Pieter