From b7e0fa64efd2c8c9fab56357872f536b7e047a79 Mon Sep 17 00:00:00 2001
From: Daniel Mack <zonque@gmail.com>
Date: Thu, 30 Aug 2012 18:52:31 +0200
Subject: [PATCH] --- yaml --- r: 322482 b: refs/heads/master c:
 2e4a263ca80a203ac6109f5932722a716c265395 h: refs/heads/master v: v3

---
 [refs]                |  2 +-
 trunk/sound/usb/pcm.c | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 4561fc087d7d..4b761bbee64d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 245baf983cc39524cce39c24d01b276e6e653c9e
+refs/heads/master: 2e4a263ca80a203ac6109f5932722a716c265395
diff --git a/trunk/sound/usb/pcm.c b/trunk/sound/usb/pcm.c
index e80b6687f43a..fd5e982fc98c 100644
--- a/trunk/sound/usb/pcm.c
+++ b/trunk/sound/usb/pcm.c
@@ -236,6 +236,21 @@ static int start_endpoints(struct snd_usb_substream *subs, int can_sleep)
 	    !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
 		struct snd_usb_endpoint *ep = subs->sync_endpoint;
 
+		if (subs->data_endpoint->iface != subs->sync_endpoint->iface ||
+		    subs->data_endpoint->alt_idx != subs->sync_endpoint->alt_idx) {
+			err = usb_set_interface(subs->dev,
+						subs->sync_endpoint->iface,
+						subs->sync_endpoint->alt_idx);
+			if (err < 0) {
+				snd_printk(KERN_ERR
+					   "%d:%d:%d: cannot set interface (%d)\n",
+					   subs->dev->devnum,
+					   subs->sync_endpoint->iface,
+					   subs->sync_endpoint->alt_idx, err);
+				return -EIO;
+			}
+		}
+
 		snd_printdd(KERN_DEBUG "Starting sync EP @%p\n", ep);
 
 		ep->sync_slave = subs->data_endpoint;