[LAD] ALSA latency and MMAP

[Paul Davis]

On Tue, Sep 8, 2009 at 2:39 AM, Clemens Ladisch<clemens at ladisch.de> wrote:
> Paul Davis wrote:
>> On Mon, Sep 7, 2009 at 10:54 AM, Clemens Ladisch<clemens at ladisch.de> wrote:
>>> Paul Davis wrote:
>>>> snd_pcm_write() and snd_pcm_read(), IIRC, allow reads&writes of chunks
>>>> of data that are not period-sized.
>>>
>>> Yes.  So does snd_pcm_mmap_commit().
>>
>> something must have changed. "back in the day", you could not possible
>> use the mmap API to deliver > 1 period at a time. has that changed?
>
> I don't know about "those days", but if that was the case then, it has
> indeed changed.

the documentation for snd_pcm_writei() notes:

"If the blocking behaviour is selected, then routine waits until all
requested bytes are played or put to the playback ring buffer. The
count of bytes can be less only if a signal or underrun occurred."

do you want to clarify your comment about "no additional buffering"?