ALSA: pcm: Preprocess PAUSED or SUSPENDED stream before PREPARE

Calling PREPARE ioctl to the stream in either PAUSED or SUSPENDED state may confuse some drivers that don't handle the state properly. Instead of fixing each driver, PCM core should take care of the proper state change before actually trying to (re-)prepare the stream. Namely, when the stream is in PAUSED state, it triggers PAUSE_RELEASE, and when in SUSPENDED state, it triggers STOP, before calling prepare callbacks. Reviewed-by: Takashi Sakamoto <[email protected]> Signed-off-by: Takashi Iwai <[email protected]>
CamonZ · Jun 14, 2017 · 1b745cd · 1b745cd
1 parent 4b95ff7
commit 1b745cd
Showing 1 changed file with 11 additions and 0 deletions.
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
@@ -1684,6 +1684,17 @@ static int snd_pcm_prepare(struct snd_pcm_substream *substream,
 	else
 		f_flags = substream->f_flags;
 
+	snd_pcm_stream_lock_irq(substream);
+	switch (substream->runtime->status->state) {
+	case SNDRV_PCM_STATE_PAUSED:
+		snd_pcm_pause(substream, 0);
+		/* fallthru */
+	case SNDRV_PCM_STATE_SUSPENDED:
+		snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
+		break;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+
 	return snd_pcm_action_nonatomic(&snd_pcm_action_prepare,
 					substream, f_flags);
 }