[LAU] Firewire latency

David Runge dave at sleepmap.de
Fri Jan 15 09:41:26 CET 2021


On 2021-01-14 20:20:55 (-0800), Len Ovens wrote:
> Playing around with an Audiofire 12 and I have just found an interesting
> limitation in latency settings. I can easily set my system up to use the
> audiofire to use either the alsa drivers or the ffado drivers and have tried
> both. I found an interesting result:
> 
> using the alsa driver my minimum latency when using JACK is 256/2. If I try
> 128/3 (or 128/2) JACK locks up and needs kill -9 to get rid of.
> 
> Using the FFADO drivers I have been running JACK at 32/2 for over an hour
> with only 1 xrun for the whole time.
> 
> So my question for anyone else who has or is using a firewire device is: Do
> you also have a similar experience? And which distro?
> 
> I am mainly asking for documentation reasons for Studio-controls

Hi Len,

yes, I experience the same with my RME Firewire 800.
While with the FFADO driver I can achieve much lower (and stable)
latencies, the ALSA driver seems to have higher (stable) latencies.
Moreover, the ALSA driver suffers from a bug in that particular case,
which introduces a ~10sec spike in IRQ interrupts (and a few thousand
Xruns due to that) every few minutes.

I have not been able to get any attention from upstream irt to this
problem, but it seems to be a known problem (at least according to FFADO
devs).
I hope this will get resolved eventually, as the ALSA integration is of
course a little more streamlined.

Last time I checked this was on the 5.9 kernel (Arch Linux, RT and
default kernels) and to my knowledge nothing has changed much on that
topic since then.

Maybe you'll be able to get the attention of the dev who ported most of
the FFADO things into ALSA land on the alsa-devel mailing list.

Best,
David

-- 
https://sleepmap.de
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <https://lists.linuxaudio.org/archives/linux-audio-user/attachments/20210115/1e33afc5/attachment.sig>


More information about the Linux-audio-user mailing list