[alsa-devel] defaults.pcm.minperiodtime 5000

Jaroslav Kysela perex at perex.cz
Thu Aug 12 08:27:23 CEST 2010

On Thu, 12 Aug 2010, Raymond Yau wrote:

> It seem that there is a bug in the patch which remove "if ( err < 0 )"
> -       if (err < 0)
>                return err;
> +       if (pcm->minperiodtime > 0) {

Thanks. It's usuall typo. Fixed now.

> http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=09879a4bb58199f64abcb8df506f917c8efc2383;hp=e6d5dcf1f625984605d362338d71162de45a6c60
> BTW , it seem this patch change the behaviour of alsa-lib too.
> all sound cards will now have a minperiodtime 5000

Nope. If application settles the period time/size, the behaviour is 
unchanged (see the min/max condition). We just want to limit the period 
sizes for applications which do not know what they are doing and allow 
any period time/sizes. It's better to limit the minimal period size to 
avoid generation of many interrupts per second in this case.


Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.

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