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List:       linux1394-devel
Subject:    RE: [Jackit-devel] alsa pcm_jack plugin
From:       Bob Ham <rah () bash ! sh>
Date:       2003-02-27 20:57:57
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On Thu, 2003-02-27 at 18:33, Mark Knecht wrote:
> Bob,

>    1394 OHCI has a few modes of operation, but the controller is a DMA
> engine that can interrupt at a number of times, one of them being when a
> Cycle Start packet arrive.

I should pay more attention :)


>    As for clock synchronization, that's going to be an interesting issue.
> I'm not sure it can be done, actually, but that's a very long conversation
> better left for later this week or next. I think we're going to have a
> number of different configurations we need to look at:
> 
> 1) A machine with a sound card and 1394. In this case I suggest the sound
> card is the Master clock and 1394 runs unsynchronized.

I really *really* want to syncronise these clocks.  Is it possible to
slave an OHCI controller's clock to one not on the bus (and thus force
the bus to slave to it aswell)?

Other than this, that's what I was thinking :)


> 2) A machine with only 1394. In this case, 1394 generates the Alsa clock,
> and we run Alsa and Jack from it. Audio, MIDI and control information is
> sent and received via 1394 as a digital stream. The 1394 clock on this
> machine will sync, by definition, with the 1394 clocks on the other
> machines.

Ditto; the 1394 dma engine acts as the alsa interrupt source, which
eventually initiates the jack graph's processing.

Bob

-- 
Bob Ham <rah@bash.sh>



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