Re: [alsa-devel] [PATCH - IOPLUG DRAIN 0/2]

On Thu, 22 Mar 2018 16:17:10 +0100, Wischer, Timo (ADITG/ESB) wrote:

...

I don't understand. The pulse plugin calls pa_stream_drain(), and pulse_wait_operation() to wait until the drain finishes. What does it have to do with threading?

As far as I understand you patch io->data->callback->drain() will not be called in nonblocking mode.

•   if (io->data->state == SND_PCM_STATE_DRAINING) {
  

•           if (io->data->nonblock)
  

•                   return -EAGAIN;
  

•           if (io->data->callback->drain) {
  

•                   err = io->data->callback->drain(io->data);
  

•                   if (err < 0)
  

•                           return err;
  

•           }
  

•   }
  
  

Therefore how should call pa_stream_drain() in case of nonblocking mode?

The application needs to sync manually via poll() instead. It's also the behavior of the kernel driver, which ioplug follows.

Takashi