[alsa-devel] 0 or EAGAIN from snd_pcm_update_avail()?

Hi all,

if snd_pcm_update_avail() gets called on a PCM device in non-blocking mode when no data is availabe jet, what is the expected return value? -0 -EAGAIN -either is valid

I am asking this question because pulseaudio expect to receive 0, but the the bluetooth headset pcm transfer callback returns EAGAIN, so I want to find out against whoms I should open a bug :)

Thanks in advance, Ludovico