Re: [Jack-Devel] About ALSA drivers for Firewire sound devices

On Wed, Jan 29, 2014 at 10:06 AM, Takashi Sakamoto
<[hidden]>wrote:

> HI,
>
> I'm a newbie for this project. I'm a ALSA/FFADO developer and currently
> working for ALSA drivers of some firewire devices.
>

Takashi, we know who you are ;)


> Finally, to JACK... I have no issue to JACK :p
>
> JACK is still a good friend to Firewire sound devices. But I inform
> three points to you.
>
> 1. Daisy-caining
> With FFADO backend, jackd can handle some firewire devices. But with
> ALSA backend, jack can't. This rule is still applied to the new drivers.
>
> When users want to use several ALSA PCM devices for firewire sound
> devices, they must write ALSA configuration with 'multi' plugin. See in
> detail:
>
> http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html#pcm_plugins_multi
>

With non-clock-synced devices these days, it is better to use JACK's own
capability for handling multiple devices. But since all the firewire
devices on a chain share the same clock, this seems right.


> Here I have to mention about MIDI functionality. When users use ALSA
> MIDI functionality, the new drivers also start streaming because
> firewire streaming includes both of PCM samples/MIDI messages.
>
> Some graphical JACK application such as 'patchage' displays ALSA MIDI
> ports when jackd is running. But users can't do this. Vise versa, when
> users use any ALSA MIDI ports, then jackd always failed.
>

Can you clarify this a bit?

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