From 8813a59ed892305b5ac1b5b901740b1ad4b5fefa Mon Sep 17 00:00:00 2001
From: John Keeping <john@metanate.com>
Date: Fri, 12 Jan 2018 18:43:32 +0000
Subject: [PATCH] usb: gadget: f_uac2: fix bFirstInterface in composite gadget
Git-commit: 8813a59ed892305b5ac1b5b901740b1ad4b5fefa
Patch-mainline: v4.16-rc3
References: bsc#1051510

If there are multiple functions associated with a configuration, then
the UAC2 interfaces may not start at zero.  Set the correct first
interface number in the association descriptor so that the audio
interfaces are enumerated correctly in this case.

Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/gadget/function/f_uac2.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -1041,6 +1041,8 @@ afunc_bind(struct usb_configuration *cfg
 		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 		return ret;
 	}
+	iad_desc.bFirstInterface = ret;
+
 	std_ac_if_desc.bInterfaceNumber = ret;
 	agdev->ac_intf = ret;
 	agdev->ac_alt = 0;