usb: gadget: f_uac2: fix bFirstInterface in composite gadget

[ Upstream commit 8813a59ed892305b5ac1b5b901740b1ad4b5fefa ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index f05c3f3e6103c61ca322da00fce6d5fc02aa1881..97cb2dfd6369751a5d03f5cbcce78b6e41f54154 100644 (file)
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -528,6 +528,8 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
                dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
                return ret;
        }
+       iad_desc.bFirstInterface = ret;
+
        std_ac_if_desc.bInterfaceNumber = ret;
        uac2->ac_intf = ret;
        uac2->ac_alt = 0;