Hello,
Le mercredi 14 novembre 2012 21:49:36, Trent Piepho a écrit :
You claim that the Gstreamer ALSA sink plugin accesses alsa-lib from two threads simultaneously. Could you elaborate on how this can happen, maybe it is easy to fix?
gstreamer has no lock around the call to snd_pcm_delay(). So it can race with snd_pcm_wait() or snd_pcm_writei(), which are called in another thread. There is a lock around the block of code calling wait()/writei(), but this lock isn't used for calling delay().
Use non-blocking I/O and poll(). Then the snd_pcm_write() calls will not sleep and can be interlocked with snd_pcm_delay() calls.
It seems that they didn't know there would be a problem.
Eh? It is rather the exception for a library to be thread-safe when using the same object in multiple threads.
It looks more like "they" did not pay attention to what they were doing.