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alberto Villa wrote:

Il 23/07/2012 12:38, Clemens Ladisch ha scritto:

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alberto Villa wrote:

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Hello, I'm going to use the MMAP feature of ALSA.

Why do you need to do this?

I need to use MMAP because we are running on an embedded system and we want to optimize its operations.

What exactly do you want to optimize? In most cases, mmap is no faster than snd_pcm_write; using mmap make sense only if the samples are generated dynamically without storing them in a userspace buffer.

It was necessary to use snd_pcm_wait() before snd_pcm_begin(), may be this the reason?

If you never wait, the buffer will be filled eventually.

Regards, Clemens