[PATCH 3.16 079/178] usb: gadget: f_uvc: Fix SuperSpeed companion descriptor's wBytesPerInterval

[Ben Hutchings]

3.16.46-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Roger Quadros <rogerq@xxxxxx>

commit 09424c50b7dff40cb30011c09114404a4656e023 upstream.

The streaming_maxburst module parameter is 0 offset (0..15)
so we must add 1 while using it for wBytesPerInterval
calculation for the SuperSpeed companion descriptor.

Without this host uvcvideo driver will always see the wrong
wBytesPerInterval for SuperSpeed uvc gadget and may not find
a suitable video interface endpoint.
e.g. for streaming_maxburst = 0 case it will always
fail as wBytePerInterval was evaluating to 0.

Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/gadget/f_uvc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/gadget/f_uvc.c
+++ b/drivers/usb/gadget/f_uvc.c
@@ -625,7 +625,7 @@ uvc_function_bind(struct usb_configurati
 	uvc_ss_streaming_comp.bMaxBurst = streaming_maxburst;
 	uvc_ss_streaming_comp.wBytesPerInterval =
 		cpu_to_le16(max_packet_size * max_packet_mult *
-			    streaming_maxburst);
+			    (streaming_maxburst + 1));
 
 	/* Allocate endpoints. */
 	ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);