[alsa-devel] Different returns from snd_pcm_readi() in differen versions from ALSA driver

PgmHelmi pgmhelmi at tele2.at
Mon Nov 8 17:06:03 CET 2010


We had to write a driver for audio playing and recording on Linux thin 
clients. We are using ALSA driver + libs for it, but we are
depending on the versions which are installed on them.

We have a certain buffer size for this and set the corresponding 
hardware and software parameters and call for capture
snd_pcm_readi(). The function returns the read buffer frames. In most 
versions this is equal to the number of wanted passed frames, but
not in all. We have ALSA driver version 1.0.15 and where the 
returned number is the same. But we have also version 1.0.21
where the returned number is the period size or a multiple of it.

So conclusion is, that something was changed between 1.0.15 and 1.0.21 
and changed back till As we are dependent on the
behaviour of the former and newer version, my question is, if there is a 
possibility to get the same behaviour in version 1.0.21?

Thank you for your answer in advance!

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