From 1b745cd97425f7b0b9d0c87c1b9766c31b7d0a7e Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 24 May 2016 15:40:03 +0200
Subject: [PATCH] ALSA: pcm: Preprocess PAUSED or SUSPENDED stream before PREPARE
Git-commit: 1b745cd97425f7b0b9d0c87c1b9766c31b7d0a7e
Patch-mainline: v4.13-rc1
References: bsc#1121278

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 <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/core/pcm_native.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 69cf9b02ac70..0941b9c92b3f 100644
--- 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);
 }
-- 
2.20.1