Re: [Jack-Devel] buffer size callback, revisit

On Wed, Feb 16, 2011 at 10:12 AM, Arne Jacobs <[hidden]> wrote:
> On a sidenote:
>
> The JACK API documentation states for the buffer size callback, that it
> is called in a "separate non RT thread", i.e., not in the process
> thread. Which sounds to me that the process callback and the buffer size
> callback can run in parallel.

where are you reading this? the docs at jackaudio.org state:

   Tell JACK to call bufsize_callback whenever the size of the the
buffer that will be passed to the
   process_callback is about to change. Clients that depend on knowing
the buffer size must
   supply a bufsize_callback before activating themselves.

> Is this really the case? It means you'd have to allocate new buffers and
> then somehow send those to the process thread in a lock-free way...?
> What if the process callback has already been called with the new buffer
> size, while the other thread is still reallocating the buffers?

this sounds like an artifact of jack2 calling everything (?) but the
process callback from a 2nd non-RT client thread. if it does this,
then its wrong, in the sense that as you noted, its unworkable. buffer
size changes and the process callback MUST be synchronous, i think.

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