Make sure to use the current alternate setting when verifying the
interface descriptors to avoid binding to an invalid interface.

This in turn could cause the driver to misbehave or trigger a WARN() in
usb_submit_urb() that kernels with panic_on_warn set would choke on.

Fixes: bdb5c57f209c ("Input: add sur40 driver for Samsung SUR40 (aka MS Surface 2.0/Pixelsense)")
Cc: stable <redacted>     # 3.13
Cc: Florian Echtler <redacted>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/input/touchscreen/sur40.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index 1dd47dda71cd..34d31c7ec8ba 100644
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c

@@ -661,7 +661,7 @@ static int sur40_probe(struct usb_interface *interface,
 	int error;
 
 	/* Check if we really have the right interface. */
-	iface_desc = &interface->altsetting[0];
+	iface_desc = interface->cur_altsetting;
 	if (iface_desc->desc.bInterfaceClass != 0xFF)
 		return -ENODEV;
 

-- 
2.24.0