Re: [Alsa-user] driver approach

[Clemens L. <cl...@la...>]

"Alexander Carôt" wrote:
> > If by 'capture delay' you mean 'the maximum delay between a sample passing
> > thru the DAC and the time it is available to be read in user space', and
> > by
> > 'blocking delay' you mean the period time, then the two should be equal
> > (ignoring interrupt and proces scheduling time).
>
> Yes - but the problem is that it is not possible to choose only one period.

The number of periods does not affect the latency (capture delay).

> With the minimum if 2 periods the capture delay is twice the blocking delay.

No, it isn't.  When your applications gets woken up by the interrupt
at the end of a period, it can handle all the data in that period.
Data that is 'older' than one period (i.e., before the previous period
boundary) was already handled by your application when it got the
previous interrupt.


HTH
Clemens