[LAU] Phonic Helix Board 24 on Fedora

Pieter Palmers pieterp at joow.be
Tue Feb 17 13:45:01 EST 2009

Fons Adriaensen wrote:
> On Mon, Feb 16, 2009 at 03:40:47PM -0800, Fernando Lopez-Lezcano wrote:
>> The issue has nothing to do with the rt patch or running with -R, it is
>> just the wrong (newer) firewire stack.
> Hmm, is that the new fireware stack that Pieter 
> told me about (IIRC at the door of the LAC2008
> LSN location) and that would actually allow to
> simplify FFADO ??

Indeed, that's the one. Unfortunately I didn't get around implementing 
FFADO support for it yet. Mostly due to lack of time. And because it 
does lack some features we need, which don't seem to be high on the 
priority list (e.g. support for multiple streams). Besides, the authors 
claim backward compatibility at the library level, i.e. libraw1394 users 
like FFADO shouldn't have to care.

But shifting it all to the 1394 guys is not completely fair. I do admit 
that we are not very noisy towards them. I guess that once more distro's 
start using the new stack that will change.

But almost a year has passed since LAC'08 and my views on the topic have 
evolved a bit. While from a theoretical perspective it should be 
possible to implement FFADO in userspace, there are some issues that 
make life a bit harder than it should be. And if it were only software 
things I could think about fixing them. But there are also some 
hardware-level issues that need workarounds that can't be done in 
userspace. If you want more details, I suggest we discuss that at the 
entrance of some obscure venue in Parma ;).

The bottom line is that I am planning to, using the current FFADO 
codebase as a reference, port the streaming code to the kernel, with a 
direct interface to ALSA. That should bring a performance improvement 
too. And it will also lighten the burden of supporting the zillion audio 
API's Linux developers seem to need.



More information about the Linux-audio-user mailing list