From ac9dd9d384b018f1e1c5a9a2686ab5605ce55818 Mon Sep 17 00:00:00 2001
From: Mark Hills <mark@pogo.org.uk>
Date: Sat, 24 Oct 2009 12:59:36 +0100
Subject: ALSA: snd-usb-caiaq: Lock on stream start/unpause

Fix a bug which can result in white noise from the driver after stream
start or unpause.

Signed-off-by: Mark Hills <mark@pogo.org.uk>
Acked-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/caiaq/audio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/usb/caiaq/audio.c b/sound/usb/caiaq/audio.c
index e76017cd5ac..86b2c3b92df 100644
--- a/sound/usb/caiaq/audio.c
+++ b/sound/usb/caiaq/audio.c
@@ -62,10 +62,14 @@ static void
 activate_substream(struct snd_usb_caiaqdev *dev,
 	           struct snd_pcm_substream *sub)
 {
+	spin_lock(&dev->spinlock);
+
 	if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		dev->sub_playback[sub->number] = sub;
 	else
 		dev->sub_capture[sub->number] = sub;
+
+	spin_unlock(&dev->spinlock);
 }
 
 static void
-- 
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