ALSA: remove unneeded power_mutex lock in snd_pcm_drop

Upstream-commit-id: 24e8fc49

The power_mutex lock in snd_pcm_drop may cause a possible deadlock
chain, and above all, it's unneeded.  Let's get rid of it.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

sound/core/pcm_native.c

@@ -1545,16 +1545,10 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream)
 	card = substream->pcm->card;
 
 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
-	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED ||
+	    runtime->status->state == SNDRV_PCM_STATE_SUSPENDED)
 		return -EBADFD;
 
-	snd_power_lock(card);
-	if (runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
-		result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
-		if (result < 0)
-			goto _unlock;
-	}
-
 	snd_pcm_stream_lock_irq(substream);
 	/* resume pause */
 	if (runtime->status->state == SNDRV_PCM_STATE_PAUSED)
@@ -1563,8 +1557,7 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream)
 	snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
 	/* runtime->control->appl_ptr = runtime->status->hw_ptr; */
 	snd_pcm_stream_unlock_irq(substream);
- _unlock:
-	snd_power_unlock(card);
+
 	return result;
 }