From 103e9625647ad74d201e26fb74afcd8479142a37 Mon Sep 17 00:00:00 2001
From: Alberto Aguirre <albaguirre@gmail.com>
Date: Wed, 18 Apr 2018 09:35:34 -0500
Subject: [PATCH] ALSA: usb-audio: simplify set_sync_ep_implicit_fb_quirk
Git-commit: 103e9625647ad74d201e26fb74afcd8479142a37
Patch-mainline: v4.18-rc1
References: bsc#1051510

Signed-off-by: Alberto Aguirre <albaguirre@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/usb/pcm.c |   52 ++++++++++++++++++++--------------------------------
 1 file changed, 20 insertions(+), 32 deletions(-)

--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -321,6 +321,7 @@ static int set_sync_ep_implicit_fb_quirk
 	struct usb_host_interface *alts;
 	struct usb_interface *iface;
 	unsigned int ep;
+	unsigned int ifnum;
 
 	/* Implicit feedback sync EPs consumers are always playback EPs */
 	if (subs->direction != SNDRV_PCM_STREAM_PLAYBACK)
@@ -330,44 +331,23 @@ static int set_sync_ep_implicit_fb_quirk
 	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
 	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */
 		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;
-		break;
+		ifnum = 3;
+		goto add_sync_ep_from_ifnum;
 	case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
 	case USB_ID(0x0763, 0x2081):
 		ep = 0x81;
-		iface = usb_ifnum_to_if(dev, 2);
-
-		if (!iface || iface->num_altsetting == 0)
-			return -EINVAL;
-
-		alts = &iface->altsetting[1];
-		goto add_sync_ep;
-	case USB_ID(0x2466, 0x8003):
+		ifnum = 2;
+		goto add_sync_ep_from_ifnum;
+	case USB_ID(0x2466, 0x8003): /* Fractal Audio Axe-Fx II */
 		ep = 0x86;
-		iface = usb_ifnum_to_if(dev, 2);
-
-		if (!iface || iface->num_altsetting == 0)
-			return -EINVAL;
-
-		alts = &iface->altsetting[1];
-		goto add_sync_ep;
-	case USB_ID(0x1397, 0x0002):
+		ifnum = 2;
+		goto add_sync_ep_from_ifnum;
+	case USB_ID(0x1397, 0x0002): /* Behringer UFX1204 */
 		ep = 0x81;
-		iface = usb_ifnum_to_if(dev, 1);
-
-		if (!iface || iface->num_altsetting == 0)
-			return -EINVAL;
-
-		alts = &iface->altsetting[1];
-		goto add_sync_ep;
-
+		ifnum = 1;
+		goto add_sync_ep_from_ifnum;
 	}
+
 	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
 	    altsd->bInterfaceProtocol == 2 &&
@@ -382,6 +362,14 @@ static int set_sync_ep_implicit_fb_quirk
 	/* No quirk */
 	return 0;
 
+add_sync_ep_from_ifnum:
+	iface = usb_ifnum_to_if(dev, ifnum);
+
+	if (!iface || iface->num_altsetting == 0)
+		return -EINVAL;
+
+	alts = &iface->altsetting[1];
+
 add_sync_ep:
 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
 						   alts, ep, !subs->direction,