ALSA: pcm: Update hardware pointer before start capture

This ensures the transfer loop won't waste a run to read the few frames (if any) between start and hw_ptr update. It will wait for the next interrupt with wait_for_avail(). Signed-off-by: Ricardo Biehl Pasquali <[email protected]> Signed-off-by: Takashi Iwai <[email protected]>
CarlFK · Sep 10, 2018 · 64b6acf · 64b6acf
1 parent 70f7922
commit 64b6acf
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
@@ -2172,6 +2172,10 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
 	if (err < 0)
 		goto _end_unlock;
 
+	runtime->twake = runtime->control->avail_min ? : 1;
+	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
+		snd_pcm_update_hw_ptr(substream);
+
 	if (!is_playback &&
 	    runtime->status->state == SNDRV_PCM_STATE_PREPARED) {
 		if (size >= runtime->start_threshold) {
@@ -2185,10 +2189,8 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
 		}
 	}
 
-	runtime->twake = runtime->control->avail_min ? : 1;
-	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
-		snd_pcm_update_hw_ptr(substream);
 	avail = snd_pcm_avail(substream);
+
 	while (size > 0) {
 		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
 		snd_pcm_uframes_t cont;