ALSA: usb-audio: remove is_playback from implicit feedback quirks

An implicit feedback endpoint can only be a capture source. The
consumer (sink) of the implicit feedback endpoint is therefore limited
to playback EPs.
Check if the target endpoint is a playback first and remove redundant
checks.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 19 insertions, 21 deletions

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index bb2e0f52e92f..af30e08e3d3b 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -334,41 +334,39 @@ static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
 {
         struct usb_host_interface *alts;
         struct usb_interface *iface;
-        int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
         int implicit_fb = 0;
         unsigned int ep;
 
+        /* Implicit feedback sync EPs consumers are always playback EPs */
+        if (subs->direction != SNDRV_PCM_STREAM_PLAYBACK)
+                return 0;
+
         switch (subs->stream->chip->usb_id) {
         case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
         case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */
-                if (is_playback) {
-                        implicit_fb = 1;
-                        ep = 0x81;
-                        iface = usb_ifnum_to_if(dev, 3);
+                implicit_fb = 1;
+                ep = 0x81;
+                iface = usb_ifnum_to_if(dev, 3);
 
-                        if (!iface || iface->num_altsetting == 0)
-                                return -EINVAL;
+                if (!iface || iface->num_altsetting == 0)
+                        return -EINVAL;
 
-                        alts = &iface->altsetting[1];
-                        goto add_sync_ep;
-                }
+                alts = &iface->altsetting[1];
+                goto add_sync_ep;
                 break;
         case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
         case USB_ID(0x0763, 0x2081):
-                if (is_playback) {
-                        implicit_fb = 1;
-                        ep = 0x81;
-                        iface = usb_ifnum_to_if(dev, 2);
+                implicit_fb = 1;
+                ep = 0x81;
+                iface = usb_ifnum_to_if(dev, 2);
 
-                        if (!iface || iface->num_altsetting == 0)
-                                return -EINVAL;
+                if (!iface || iface->num_altsetting == 0)
+                        return -EINVAL;
 
-                        alts = &iface->altsetting[1];
-                        goto add_sync_ep;
-                }
+                alts = &iface->altsetting[1];
+                goto add_sync_ep;
         }
-        if (is_playback &&
-            attr == USB_ENDPOINT_SYNC_ASYNC &&
+        if (attr == USB_ENDPOINT_SYNC_ASYNC &&
             altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
             altsd->bInterfaceProtocol == 2 &&
             altsd->bNumEndpoints == 1 &&