[alsa-devel] Should snd_pcm_drop() interrupt snd_pcm_writei() call?

Takashi Iwai tiwai at suse.de
Fri May 15 17:16:50 CEST 2009

At Fri, 15 May 2009 15:57:49 +0200 (CEST),
Marek Peca wrote:
> > I would like to know, how should snd_pcm_drop() call influence 
> > snd_pcm_writei() being simultaneously executed.
> >
> > I expected, that after issuing snd_pcm_drop() (from another thread), the 
> > snd_pcm_write*() in progress should be terminated almost immediately with 
> > some return value (error or short write).
> > (..)
> Today, Jara Kysela told me, that calling pcm functions from multiple 
> threads is not recommended practice.
> This explains the problems I encountered. I missed the information, that 
> these functions are not meant to be thread-safe.

Although it's not recommended, the behavior you described sounds strange.
Could you check whether this still happens with the very latest
alsa-lib version?  Also I guess this depends on the plugin to be used,
e.g. dmix or not.


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