[FT C400, PATCH RFC, v3 9/9] usb-audio: FT C400 sync playback EP to capture EP

[Eldad Zack <eldad@fogrefinery.com>]

The playback endpoint uses implicit feedback mode, similiar
to the M-Audio FTU. Like with the FTU, we need to associate
the sync pipe ourselves.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
---
 sound/usb/pcm.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index ff8cbbf..4813cdc 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -372,6 +372,19 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
 			alts = &iface->altsetting[1];
 			goto add_sync_ep;
 		}
+		break;
+	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
+		if (is_playback) {
+			implicit_fb = 1;
+			ep = 0x81;
+			iface = usb_ifnum_to_if(dev, 3);
+
+			if (!iface || iface->num_altsetting == 0)
+				return -EINVAL;
+
+			alts = &iface->altsetting[1];
+			goto add_sync_ep;
+		}
 	}
 
 	if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
-- 
1.7.8.6