[PATCH 3.18 127/145] usb: gadget: f_uvc: Fix SuperSpeed companion descriptors wBytesPerInterval

Greg Kroah-Hartman
2017-04-16T10:57:25Z

From: Roger Quadros <rogerq@ti.com>

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@ideasonboard.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/gadget/function/f_uvc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -643,7 +643,7 @@ uvc_function_bind(struct usb_configurati
uvc_ss_streaming_comp.bMaxBurst = opts->streaming_maxburst;
uvc_ss_streaming_comp.wBytesPerInterval =
cpu_to_le16(max_packet_size * max_packet_mult *
- opts->streaming_maxburst);
+ (opts->streaming_maxburst + 1));

/* Allocate endpoints. */
ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);