diff --git a/sound/usb/usx2y/usbusx2y.c b/sound/usb/usx2y/usbusx2y.c
index e38c87302b15..91e0e2a4808c 100644
--- a/sound/usb/usx2y/usbusx2y.c
+++ b/sound/usb/usx2y/usbusx2y.c
@@ -353,7 +353,7 @@ static int usX2Y_create_card(struct usb_device *device,
 	card->private_free = snd_usX2Y_card_private_free;
 	usX2Y(card)->dev = device;
 	init_waitqueue_head(&usX2Y(card)->prepare_wait_queue);
-	mutex_init(&usX2Y(card)->prepare_mutex);
+	mutex_init(&usX2Y(card)->pcm_mutex);
 	INIT_LIST_HEAD(&usX2Y(card)->midi_list);
 	strcpy(card->driver, "USB "NAME_ALLCAPS"");
 	sprintf(card->shortname, "TASCAM "NAME_ALLCAPS"");
diff --git a/sound/usb/usx2y/usbusx2y.h b/sound/usb/usx2y/usbusx2y.h
index e43c0a86441a..6ae6b0806938 100644
--- a/sound/usb/usx2y/usbusx2y.h
+++ b/sound/usb/usx2y/usbusx2y.h
@@ -36,7 +36,7 @@ struct usX2Ydev {
 	unsigned int		rate,
 				format;
 	int			chip_status;
-	struct mutex		prepare_mutex;
+	struct mutex		pcm_mutex;
 	struct us428ctls_sharedmem	*us428ctls_sharedmem;
 	int			wait_iso_frame;
 	wait_queue_head_t	us428ctls_wait_queue_head;
diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c
index 6234a51625b1..a63330dd1407 100644
--- a/sound/usb/usx2y/usbusx2yaudio.c
+++ b/sound/usb/usx2y/usbusx2yaudio.c
@@ -752,36 +752,44 @@ static int snd_usX2Y_pcm_hw_params(struct snd_pcm_substream *substream,
 	unsigned int		rate = params_rate(hw_params);
 	snd_pcm_format_t	format = params_format(hw_params);
 	struct snd_card *card = substream->pstr->pcm->card;
-	struct list_head *list;
+	struct usX2Ydev	*dev = usX2Y(card);
+	int i;
 
+	mutex_lock(&usX2Y(card)->pcm_mutex);
 	snd_printdd("snd_usX2Y_hw_params(%p, %p)\n", substream, hw_params);
-	// all pcm substreams off one usX2Y have to operate at the same rate & format
-	list_for_each(list, &card->devices) {
-		struct snd_device *dev;
-		struct snd_pcm *pcm;
-		int s;
-		dev = snd_device(list);
-		if (dev->type != SNDRV_DEV_PCM)
+	/* all pcm substreams off one usX2Y have to operate at the same
+	 * rate & format
+	 */
+	for (i = 0; i < dev->pcm_devs * 2; i++) {
+		struct snd_usX2Y_substream *subs = dev->subs[i];
+		struct snd_pcm_substream *test_substream;
+
+		if (!subs)
 			continue;
-		pcm = dev->device_data;
-		for (s = 0; s < 2; ++s) {
-			struct snd_pcm_substream *test_substream;
-			test_substream = pcm->streams[s].substream;
-			if (test_substream && test_substream != substream  &&
-			    test_substream->runtime &&
-			    ((test_substream->runtime->format &&
-			      test_substream->runtime->format != format) ||
-			     (test_substream->runtime->rate &&
-			      test_substream->runtime->rate != rate)))
-				return -EINVAL;
+		test_substream = subs->pcm_substream;
+		if (!test_substream || test_substream == substream ||
+		    !test_substream->runtime)
+			continue;
+		if ((test_substream->runtime->format &&
+		     test_substream->runtime->format != format) ||
+		    (test_substream->runtime->rate &&
+		     test_substream->runtime->rate != rate)) {
+			err = -EINVAL;
+			goto error;
 		}
 	}
-	if (0 > (err = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params)))) {
+
+	err = snd_pcm_lib_malloc_pages(substream,
+				       params_buffer_bytes(hw_params));
+	if (err < 0) {
 		snd_printk(KERN_ERR "snd_pcm_lib_malloc_pages(%p, %i) returned %i\n",
 			   substream, params_buffer_bytes(hw_params), err);
-		return err;
+		goto error;
 	}
-	return 0;
+
+ error:
+	mutex_unlock(&usX2Y(card)->pcm_mutex);
+	return err;
 }
 
 /*
@@ -791,7 +799,7 @@ static int snd_usX2Y_pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_usX2Y_substream *subs = runtime->private_data;
-	mutex_lock(&subs->usX2Y->prepare_mutex);
+	mutex_lock(&subs->usX2Y->pcm_mutex);
 	snd_printdd("snd_usX2Y_hw_free(%p)\n", substream);
 
 	if (SNDRV_PCM_STREAM_PLAYBACK == substream->stream) {
@@ -812,7 +820,7 @@ static int snd_usX2Y_pcm_hw_free(struct snd_pcm_substream *substream)
 			usX2Y_urbs_release(subs);
 		}
 	}
-	mutex_unlock(&subs->usX2Y->prepare_mutex);
+	mutex_unlock(&subs->usX2Y->pcm_mutex);
 	return snd_pcm_lib_free_pages(substream);
 }
 /*
@@ -829,7 +837,7 @@ static int snd_usX2Y_pcm_prepare(struct snd_pcm_substream *substream)
 	int err = 0;
 	snd_printdd("snd_usX2Y_pcm_prepare(%p)\n", substream);
 
-	mutex_lock(&usX2Y->prepare_mutex);
+	mutex_lock(&usX2Y->pcm_mutex);
 	usX2Y_subs_prepare(subs);
 // Start hardware streams
 // SyncStream first....
@@ -849,7 +857,7 @@ static int snd_usX2Y_pcm_prepare(struct snd_pcm_substream *substream)
 		err = usX2Y_urbs_start(subs);
 
  up_prepare_mutex:
-	mutex_unlock(&usX2Y->prepare_mutex);
+	mutex_unlock(&usX2Y->pcm_mutex);
 	return err;
 }
 
diff --git a/sound/usb/usx2y/usx2yhwdeppcm.c b/sound/usb/usx2y/usx2yhwdeppcm.c
index 814d0e887c62..90766a92e7fd 100644
--- a/sound/usb/usx2y/usx2yhwdeppcm.c
+++ b/sound/usb/usx2y/usx2yhwdeppcm.c
@@ -358,7 +358,7 @@ static int snd_usX2Y_usbpcm_hw_free(struct snd_pcm_substream *substream)
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_usX2Y_substream *subs = runtime->private_data,
 		*cap_subs2 = subs->usX2Y->subs[SNDRV_PCM_STREAM_CAPTURE + 2];
-	mutex_lock(&subs->usX2Y->prepare_mutex);
+	mutex_lock(&subs->usX2Y->pcm_mutex);
 	snd_printdd("snd_usX2Y_usbpcm_hw_free(%p)\n", substream);
 
 	if (SNDRV_PCM_STREAM_PLAYBACK == substream->stream) {
@@ -387,7 +387,7 @@ static int snd_usX2Y_usbpcm_hw_free(struct snd_pcm_substream *substream)
 				usX2Y_usbpcm_urbs_release(cap_subs2);
 		}
 	}
-	mutex_unlock(&subs->usX2Y->prepare_mutex);
+	mutex_unlock(&subs->usX2Y->pcm_mutex);
 	return snd_pcm_lib_free_pages(substream);
 }
 
@@ -493,7 +493,7 @@ static int snd_usX2Y_usbpcm_prepare(struct snd_pcm_substream *substream)
 		memset(usX2Y->hwdep_pcm_shm, 0, sizeof(struct snd_usX2Y_hwdep_pcm_shm));
 	}
 
-	mutex_lock(&usX2Y->prepare_mutex);
+	mutex_lock(&usX2Y->pcm_mutex);
 	usX2Y_subs_prepare(subs);
 // Start hardware streams
 // SyncStream first....
@@ -534,7 +534,7 @@ static int snd_usX2Y_usbpcm_prepare(struct snd_pcm_substream *substream)
 		usX2Y->hwdep_pcm_shm->capture_iso_start = -1;
 
  up_prepare_mutex:
-	mutex_unlock(&usX2Y->prepare_mutex);
+	mutex_unlock(&usX2Y->pcm_mutex);
 	return err;
 }
 
@@ -600,59 +600,30 @@ static struct snd_pcm_ops snd_usX2Y_usbpcm_ops =
 };
 
 
-static int usX2Y_pcms_lock_check(struct snd_card *card)
+static int usX2Y_pcms_busy_check(struct snd_card *card)
 {
-	struct list_head *list;
-	struct snd_device *dev;
-	struct snd_pcm *pcm;
-	int err = 0;
-	list_for_each(list, &card->devices) {
-		dev = snd_device(list);
-		if (dev->type != SNDRV_DEV_PCM)
-			continue;
-		pcm = dev->device_data;
-		mutex_lock(&pcm->open_mutex);
+	struct usX2Ydev	*dev = usX2Y(card);
+	int i;
+
+	for (i = 0; i < dev->pcm_devs * 2; i++) {
+		struct snd_usX2Y_substream *subs = dev->subs[i];
+		if (subs && subs->pcm_substream &&
+		    SUBSTREAM_BUSY(subs->pcm_substream))
+			return -EBUSY;
 	}
-	list_for_each(list, &card->devices) {
-		int s;
-		dev = snd_device(list);
-		if (dev->type != SNDRV_DEV_PCM)
-			continue;
-		pcm = dev->device_data;
-		for (s = 0; s < 2; ++s) {
-			struct snd_pcm_substream *substream;
-			substream = pcm->streams[s].substream;
-			if (substream && SUBSTREAM_BUSY(substream))
-				err = -EBUSY;
-		}
-	}
-	return err;
+	return 0;
 }
 
-
-static void usX2Y_pcms_unlock(struct snd_card *card)
-{
-	struct list_head *list;
-	struct snd_device *dev;
-	struct snd_pcm *pcm;
-	list_for_each(list, &card->devices) {
-		dev = snd_device(list);
-		if (dev->type != SNDRV_DEV_PCM)
-			continue;
-		pcm = dev->device_data;
-		mutex_unlock(&pcm->open_mutex);
-	}
-}
-
-
 static int snd_usX2Y_hwdep_pcm_open(struct snd_hwdep *hw, struct file *file)
 {
-	// we need to be the first 
 	struct snd_card *card = hw->card;
-	int err = usX2Y_pcms_lock_check(card);
-	if (0 == err)
+	int err;
+
+	mutex_lock(&usX2Y(card)->pcm_mutex);
+	err = usX2Y_pcms_busy_check(card);
+	if (!err)
 		usX2Y(card)->chip_status |= USX2Y_STAT_CHIP_MMAP_PCM_URBS;
-	usX2Y_pcms_unlock(card);
+	mutex_unlock(&usX2Y(card)->pcm_mutex);
 	return err;
 }
 
@@ -660,10 +631,13 @@ static int snd_usX2Y_hwdep_pcm_open(struct snd_hwdep *hw, struct file *file)
 static int snd_usX2Y_hwdep_pcm_release(struct snd_hwdep *hw, struct file *file)
 {
 	struct snd_card *card = hw->card;
-	int err = usX2Y_pcms_lock_check(card);
-	if (0 == err)
+	int err;
+
+	mutex_lock(&usX2Y(card)->pcm_mutex);
+	err = usX2Y_pcms_busy_check(card);
+	if (!err)
 		usX2Y(hw->card)->chip_status &= ~USX2Y_STAT_CHIP_MMAP_PCM_URBS;
-	usX2Y_pcms_unlock(card);
+	mutex_unlock(&usX2Y(card)->pcm_mutex);
 	return err;
 }