[LAD] JACK sample rate pull up/down

Adrian Knoth adi at drcomp.erfurt.thur.de
Mon Jun 15 11:33:54 UTC 2015


On 06/13/15 04:02, Reuben Martin wrote:

> Does anybody know if there is any way to pull up/down with JACK? And
> if there is, can ALSA deal with it very gracefully?

While you cannot do pull-up/down with jack, you can at least do it on
(most) RME cards on the ALSA side.

If you have a card with a TCO option, the pull controls are directly
exposed to ALSA.

For non-TCO cards, you can set the system sample rate with 1Hz
granularity via the "System Sample Rate" control.

And while jackd blindly believes in the 48000 it originally requested,
you're actually running at whatever you want. ;)

I've implemented it in the HDSPM driver. If you happen to have a card
that uses HDSP instead, I'm somewhat confident it could be ported.
Here's the code in question:

 
http://lxr.free-electrons.com/source/sound/pci/rme9652/hdspm.c?v=3.19#L2229


Cheers


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