--- linux-4.9.37/drivers/usb/gadget/Kconfig	2017-07-12 16:42:41.000000000 +0300
+++ linux-4.9.y/drivers/usb/gadget/Kconfig	2021-06-07 13:01:34.000000000 +0300
@@ -158,6 +158,9 @@
 config USB_U_ETHER
 	tristate
 
+config USB_U_AUDIO
+	tristate
+
 config USB_F_SERIAL
 	tristate
 
@@ -381,6 +384,7 @@
 	depends on SND
 	select USB_LIBCOMPOSITE
 	select SND_PCM
+	select USB_U_AUDIO
 	select USB_F_UAC2
 	help
 	  This Audio function is compatible with USB Audio Class