[alsa-devel] defaults.pcm.minperiodtime 5000
Raymond Yau
superquad.vortex2 at gmail.com
Thu Sep 2 10:09:20 CEST 2010
2010/8/12 Jaroslav Kysela <perex at perex.cz>
> On Thu, 12 Aug 2010, Raymond Yau wrote:
>
>>
>> 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.
>
>
This mean that if application did not set sample rate by using
snd_pcm_hw_params_set_rate_near() , alsa-lib will select default rate
(minimum rate of 1 Hz for alsa-pulse plugin )
err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_RATE,
1, PA_RATE_MAX);
This kind of application cause PA server aborted immediately in Fedora 10
and Fedora 13
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