BLOCK_TRANSFER flag in snd_pcm_hardware_t structure

BLOCK_TRANSFER flag in snd_pcm_hardware_t structure

[Marc Titinger]

Hi All,

I can't figure out from the code what are the implications of having the flag SNDRV_PCM_INFO_BLOCK_TRANSFER set in a snd_pcm_hardware_t.info field ?
is this flag linked to the values of .period_bytes_min/max or .fifo_size ?
is this related to the hw_ptr granularity ?

tx
Marc.


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Re: BLOCK_TRANSFER flag in snd_pcm_hardware_t structure

[Jaroslav Kysela]

On Wed, 19 Feb 2003, Marc Titinger wrote:

> Hi All,
> 
> I can't figure out from the code what are the implications of having the flag SNDRV_PCM_INFO_BLOCK_TRANSFER set in a snd_pcm_hardware_t.info field ?
> is this flag linked to the values of .period_bytes_min/max or .fifo_size ?
> is this related to the hw_ptr granularity ?

It's not related to anything which application can determine. Please, 
don't rely so much on this flag. It is not well defined.

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs



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Re: BLOCK_TRANSFER flag in snd_pcm_hardware_t structure

[Takashi Iwai]

At Wed, 19 Feb 2003 18:06:22 +0100,
Marc Titinger wrote:
> 
> Hi All,
> 
> I can't figure out from the code what are the implications of having
> the flag SNDRV_PCM_INFO_BLOCK_TRANSFER set in a
> snd_pcm_hardware_t.info field ? 

this is an inherited flag from the older version, and plays no big
role now.  it's still checked in the OSS emulation code, though.

> is this flag linked to the values of .period_bytes_min/max or .fifo_size ?

no.

> is this related to the hw_ptr granularity ?

no.  hw_ptr granularity is defined only by period_bytes_min (and
additional constraints if any).


Takashi


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