参照元

説明

引数

返り値

参考

実装

/**
 * snd_pcm_period_elapsed - update the pcm status for the next period
 * @substream: the pcm substream instance
 *
 * This function is called from the interrupt handler when the
 * PCM has processed the period size.  It will update the current
 * pointer, wake up sleepers, etc.
 *
 * Even if more than one periods have elapsed since the last call, you
 * have to call this only once.
 */
void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime;
	unsigned long flags;
	if (PCM_RUNTIME_CHECK(substream))
		return;
	runtime = substream->runtime;
	if (runtime->transfer_ack_begin)
		runtime->transfer_ack_begin(substream);

	snd_pcm_stream_lock_irqsave(substream, flags);
	if (!snd_pcm_running(substream) ||
	    snd_pcm_update_hw_ptr_interrupt(substream) < 0)
		goto _end;
	if (substream->timer_running)
		snd_timer_interrupt(substream->timer, 1);
 _end:
	snd_pcm_stream_unlock_irqrestore(substream, flags);
	if (runtime->transfer_ack_end)
		runtime->transfer_ack_end(substream);
	kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
}

EXPORT_SYMBOL(snd_pcm_period_elapsed);

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