ALSA: usb-audio: Fix implicit fb endpoint setup by quirk

manuel-rhdt · tiwai · commit 2bc16b9f3223 · 2019-02-07T20:04:43.000+01:00
The commit a60945f ("ALSA: usb-audio: move implicit fb quirks to separate function") introduced an error in the handling of quirks for implicit feedback endpoints. This commit fixes this. If a quirk successfully sets up an implicit feedback endpoint, usb-audio no longer tries to find the implicit fb endpoint itself. Fixes: a60945f ("ALSA: usb-audio: move implicit fb quirks to separate function") Signed-off-by: Manuel Reinhardt <manuel.rhdt@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
@@ -314,6 +314,9 @@ static int search_roland_implicit_fb(struct usb_device *dev, int ifnum,
 	return 0;
 }
 
+/* Setup an implicit feedback endpoint from a quirk. Returns 0 if no quirk
+ * applies. Returns 1 if a quirk was found.
+ */
 static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
 					 struct usb_device *dev,
 					 struct usb_interface_descriptor *altsd,
@@ -384,7 +387,7 @@ static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
 
 	subs->data_endpoint->sync_master = subs->sync_endpoint;
 
-	return 0;
+	return 1;
 }
 
 static int set_sync_endpoint(struct snd_usb_substream *subs,
@@ -423,6 +426,10 @@ static int set_sync_endpoint(struct snd_usb_substream *subs,
 	if (err < 0)
 		return err;
 
+	/* endpoint set by quirk */
+	if (err > 0)
+		return 0;
+
 	if (altsd->bNumEndpoints < 2)
 		return 0;
 
