[LAD] ALSA latency and MMAP

[Jussi Laako]

Paul Davis wrote:
> 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?

Reading
http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___direct.html
at least I understand that readi/writei/readn/writen are just helper
functions around mmap_begin/mmap_commit.

Essentially it should be possible to do read/modify/write as well as the
memcpy actions on mmap buffer, because former can be implemented in user
space using latter...


	- Jussi