Re: Click after draining

[Takashi Iwai <tiwai@suse.de>]

At Mon, 18 Oct 2004 17:34:02 +0200 (CEST),
Giuliano Pochini wrote:
> 
> 
> On 18-Oct-2004 Takashi Iwai wrote:
> 
> >> > The period size is always same even for the last period, AFAIK.
> >> 
> >> Only if the driver explicitly asks for it by calling
> >> snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS).
> > 
> > No, this means that buffer_size = N * period_size, where N is
> > integer.  Without this constraint, N doesn't have to be an integer.
> 
> 
> Yes, exactly. If N isn't integer, the buffer is formed by
> bufsize\persize periods (== the integer part of N) plus one
> short period which is bufsize%persize long.

The period size is constant regardless of N because it simply defines
the interval of interrupts.  When N isn't integer (say, 2.5), the
transfer point moves like:

	0, 1, 2, 0.5, 1.5, 0, 1, ...

That is, when the point is at 2, the transfer is split to two parts
(2-2.5 and 0-0.5).


Takashi


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