[PATCH 2/2] usb: gadget: f_uvc: Sanity check wMaxPacketSize for SuperSpeed

[Roger Quadros]

As per USB3.0 Specification "Table 9-20. Standard Endpoint Descriptor",
for interrupt and isochronous endpoints, wMaxPacketSize must be set to
1024 if the endpoint defines bMaxBurst to be greater than zero.

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
 drivers/usb/gadget/function/f_uvc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index c7689d0..f8a1881 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -594,6 +594,14 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	opts->streaming_maxpacket = clamp(opts->streaming_maxpacket, 1U, 3072U);
 	opts->streaming_maxburst = min(opts->streaming_maxburst, 15U);
 
+	/* For SS, wMaxPacketSize has to be 1024 if bMaxBurst is not 0 */
+	if (opts->streaming_maxburst &&
+	    (opts->streaming_maxpacket % 1024) != 0) {
+		opts->streaming_maxpacket = roundup(opts->streaming_maxpacket, 1024);
+		INFO(cdev, "overriding streaming_maxpacket to %d\n",
+		     opts->streaming_maxpacket);
+	}
+
 	/* Fill in the FS/HS/SS Video Streaming specific descriptors from the
 	 * module parameters.
 	 *
-- 
2.7.4