Re: [Jack-Devel] driver_null_cycle

I think I understand what the driver_wait function is doing ...
It appears that the driver_wait function is trying to work out how much 
time has passed since the last transport_cycle_start and if it has taken 
too long, then it reports an error.

But the null_cycle is still confusing.

Matt

On 15/01/14 14:53, Matt Flax wrote:
> Is Jack requesting samples to be dropped in the null_cycle ? For 
> example if I am using a ring_buffer with a DMA loading it ... is it 
> necessary to fast forward the beginning of the ring buffer by nframes ?
>
> W.r.t. the driver_wait function, on the understanding that the system 
> I am looking at uses a ring buffer and DMA, in your opinion, is it 
> possible to re-use the dummy_driver_wait function ?
>
> thanks
> Matt
>
>
>
> On 15/01/14 14:11, Paul Davis wrote:
>>
>>
>>
>> On Tue, Jan 14, 2014 at 10:01 PM, Matt Flax <[hidden] 
>> <mailto:[hidden]>> wrote:
>>
>>     Hi there,
>>
>>     Can someone please clarify the driver_null_cycle function for me ?
>>
>>     The function is defined as so :
>>     static int you_driver_null_cycle (you_driver_t *driver,
>>     jack_nframes_t nframes);
>>
>>     My question is w.r.t. the nframes. Is this function meant to
>>     flush nframes from the audio stream ?
>>
>>     Here is what is written in include/driver.h
>>        The JACK engine will call this after the wait function (above) has
>>        been called, but for some reason the engine is unable to execute
>>        a full "cycle". the driver should do whatever is necessary to
>>        keep itself running correctly, but cannot reference ports
>>        or other JACK data structures in any way.
>>
>>
>> "the driver should do whatever is necessary to keep itself running 
>> correctly"
>>
>> that's about the core of it. what that is depends on the driver and 
>> in turn on the device.
>>
>

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