A question re normal internal operation of ALSA. I'm using the poll() interface to wait for a audio playback device to ask for more samples. The device is in the PREPARED state, not RUNNING state. At the beginning of my program, _before_ I write any samples to it, I'm getting repeated POLLOUT events, when I do not yet have data available to send. They seem to come frequent enough to load down my CPU, rather than every N ticks, so it seems. I thought a device was idle in the PREPARED state, and you had to either set the start conditions and write data, or explicitly invoke snd_pcm_start(). In my case, I wanted to use snd_pcm_start() once I had data to send, and also used the start conditions, set at 50%, to cause the audio output to them proceed to the speaker. The output snd_pcm_status_dump() right after exiting from the very first poll() ever in the program shows the following, and that I have a POLLOUT event pending. --- Status of Headphones Player --- state : PREPARED trigger_time: 0.000000 tstamp : 1176119509.658821000 delay : 0 avail : 2400 avail_max : 0 POLLOUT fired, calling ready_for_write() I suppose I could force it back to an earlier state like SND_PCM_STATE_OPEN or SND_PCM_STATE_SETUP, but that seems a bit harsh, since the snd_pcm_hw_params() takes it to the SND_PCM_STATE_PREPARED itself. Thanks for any tips, -Jeff _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
