Kontron KTAM3874-pITX - Manual (Page 98)

KTD-S0057-I Page 94 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
/* Underrun and suspend recovery */
static int xrun_recovery (snd_pcm_t *handle, int err)
{
if
(verbose)
printf("Stream recovery\n");
if (err == -EPIPE) /* under-run */
{
err = snd_pcm_prepare (handle);
if (err < 0)
printf ("Can't recovery from underrun, prepare failed: %s\n", snd_strerror (err));
return 0;
}
else if (err == -ESTRPIPE)
{
while ((err = snd_pcm_resume (handle)) == -EAGAIN)
sleep (1); /* wait until the suspend flag is released */
if (err < 0)
{
err = snd_pcm_prepare (handle);
if (err < 0)
printf ("Can't recovery from suspend, prepare failed: %s\n", snd_strerror (err));
}
return 0;
}
return err;
}
/* Transfer method - write only */
static int write_loop (snd_pcm_t *handle, signed short *samples, snd_pcm_channel_area_t *areas)
{
double phase = 0;
signed short *ptr;
int err, cptr;
while (1)
{
generate_sine (areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
while (cptr > 0)
{
err = snd_pcm_writei (handle, ptr, cptr);
if (err == -EAGAIN)
continue;
if (err < 0)
{
if (xrun_recovery (handle, err) < 0)
{
printf ("Write error: %s\n", snd_strerror (err));
exit (EXIT_FAILURE);
}