Commit 4bbe1ddf authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: Add extra delay count in PCM 



Added runtime->delay field to adjust the delayed samples for snd_pcm_delay().
Typically a hardware FIFO length is stored in this field, so that the
extra delay between hwptr and applptr can be computed.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 091438dd

include/sound/pcm.h

+1 −0
Original line number Diff line number Diff line
@@ -270,6 +270,7 @@ struct snd_pcm_runtime { 
	snd_pcm_uframes_t hw_ptr_base;	/* Position at buffer restart */

	snd_pcm_uframes_t hw_ptr_interrupt; /* Position at interrupt time */

	unsigned long hw_ptr_jiffies;	/* Time when hw_ptr is updated */

	snd_pcm_sframes_t delay;	/* extra delay; typically FIFO size */



	/* -- HW params -- */

	snd_pcm_access_t access;	/* access mode */

sound/core/pcm_native.c

+5 −3
Original line number Diff line number Diff line
@@ -587,14 +587,15 @@ int snd_pcm_status(struct snd_pcm_substream *substream, 
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

		status->avail = snd_pcm_playback_avail(runtime);

		if (runtime->status->state == SNDRV_PCM_STATE_RUNNING ||

		    runtime->status->state == SNDRV_PCM_STATE_DRAINING)

		    runtime->status->state == SNDRV_PCM_STATE_DRAINING) {

			status->delay = runtime->buffer_size - status->avail;

		else

			status->delay += runtime->delay;

		} else

			status->delay = 0;

	} else {

		status->avail = snd_pcm_capture_avail(runtime);

		if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)

			status->delay = status->avail;

			status->delay = status->avail + runtime->delay;

		else

			status->delay = 0;

	}
@@ -2404,6 +2405,7 @@ static int snd_pcm_delay(struct snd_pcm_substream *substream, 
			n = snd_pcm_playback_hw_avail(runtime);

		else

			n = snd_pcm_capture_avail(runtime);

		n += runtime->delay;

		break;

	case SNDRV_PCM_STATE_XRUN:

		err = -EPIPE;