Re: [PATCH 1/2] usb: gadget: f_uvc: Fix SuperSpeed companion descriptor's wBytesPerInterval

From: Roger Quadros
Date: Thu Mar 09 2017 - 04:37:20 EST


Felipe,

On 08/03/17 16:05, Roger Quadros wrote:
> 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.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Roger Quadros <rogerq@xxxxxx>

Please pick this one for v4.11-rc with Laurent's Reviewed-by. Thanks.

> ---
> drivers/usb/gadget/function/f_uvc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index 29b41b5..c7689d0 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -625,7 +625,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
> 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);
>

--
cheers,
-roger