Hi Tony,

On Friday 13 July 2012 16:41:13 Tony. Nie wrote:
> Hi ALL,
> 
> I just found that Realtek's USB3.0 camera RTS5825 cannot work on usb3.0
> mode, and find a issue in UVC driver.
> 
> USB group had changed the means of wMaxPacketSize of endpoint descriptor
> from USB2.0 to USB3.0, Please refer to the section 9.6.6 of USB
> specification(U2 and U3).
> 
> I think the method of calculating maximum packet size of usb3.0 isoc
> endpoint should differ from usb2.0.
> While in the lasted UVC driver, the algorism was according to usb2.0
> spec in function uvc_init_video_isoc and
> uvc_init_video. Is it wrong?

This can indeed be a problem. Could you please send me the lsusb -v output for 
that device ?

> -------- Original Message --------
> Subject:      [PATCH] uvcvideo:Support for Realtek USB3.0 WebCam
> Date:         Thu, 7 Jun 2012 11:44:05 +0800
> From:         聂江涛 <tony_...@realsil.com.cn>
> To:   linux-media@vger.kernel.org <linux-media@vger.kernel.org>
> CC:   聂江涛 <tony_...@realsil.com.cn>
> 
> From: Tony.Nie <tony_...@realsil.com.cn>
> 
> The method of calculating max bandwidth of usb2.0 isoc endpoint differed
> from usb3.0. The uvc_init_videio() and uvc_init_video_isoc() must be
> re-implemented to get correct packet size.
> 
> Signed-off-by: Tony.Nie <tony_...@realsil.com.cn>
> ---
>  drivers/media/video/uvc/uvc_video.c |   47
> +++++++++++++++++++++++++++++------ 1 files changed, 39 insertions(+), 8
> deletions(-)
> 
> diff --git a/drivers/media/video/uvc/uvc_video.c
> b/drivers/media/video/uvc/uvc_video.c index b76b0ac..5915377 100644
> --- a/drivers/media/video/uvc/uvc_video.c
> +++ b/drivers/media/video/uvc/uvc_video.c
> @@ -1441,13 +1441,23 @@ static void uvc_uninit_video(struct uvc_streaming
> *stream, int free_buffers) static int uvc_init_video_isoc(struct
> uvc_streaming *stream,
>       struct usb_host_endpoint *ep, gfp_t gfp_flags)
>  {
> +     struct usb_interface *intf = stream->intf;
> +     struct usb_device *udev = interface_to_usbdev(intf);
>       struct urb *urb;
>       unsigned int npackets, i, j;
>       u16 psize;
>       u32 size;
> 
> -     psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> -     psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
> +     if (udev->speed == USB_SPEED_SUPER) {
> +             int mult = (ep->ss_ep_comp.bmAttributes & 0X3) + 1;
> +             int burst = ep->ss_ep_comp.bMaxBurst + 1;
> +             psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> +             psize = psize * mult * burst;
> +     } else {
> +             psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> +             psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
> +     }
> +
>       size = stream->ctrl.dwMaxVideoFrameSize;
> 
>       npackets = uvc_alloc_urb_buffers(stream, size, psize, gfp_flags);
> @@ -1549,6 +1559,7 @@ static int uvc_init_video_bulk(struct uvc_streaming
> *stream, static int uvc_init_video(struct uvc_streaming *stream, gfp_t
> gfp_flags) {
>       struct usb_interface *intf = stream->intf;
> +     struct usb_device *udev = interface_to_usbdev(intf);
>       struct usb_host_endpoint *ep;
>       unsigned int i;
>       int ret;
> @@ -1580,6 +1591,8 @@ static int uvc_init_video(struct uvc_streaming
> *stream, gfp_t gfp_flags) "B/frame bandwidth.\n", bandwidth);
>               }
> 
> +             if (udev->speed == USB_SPEED_SUPER)
> +                     best_psize = 1024 * 16 * 3;
>               for (i = 0; i < intf->num_altsetting; ++i) {
>                       struct usb_host_interface *alts;
>                       unsigned int psize;
> @@ -1591,12 +1604,30 @@ static int uvc_init_video(struct uvc_streaming
> *stream, gfp_t gfp_flags) continue;
> 
>                       /* Check if the bandwidth is high enough. */
> -                     psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> -                     psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
> -                     if (psize >= bandwidth && psize <= best_psize) {
> -                             altsetting = i;
> -                             best_psize = psize;
> -                             best_ep = ep;
> +                     if (udev->speed == USB_SPEED_HIGH) {

What about full speed devices ?

> +                             psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> +                             psize = (psize & 0x07ff) *
> +                                     (1 + ((psize >> 11) & 3));
> +                             if (psize >= bandwidth && psize <= best_psize) {
> +                                     altsetting = i;
> +                                     best_psize = psize;
> +                                     best_ep = ep;
> +                             }

This test is copied in the next branch of the outer if and can be moved after 
it.

> +                     } else if (udev->speed == USB_SPEED_SUPER) {
> +                             int mult = 1 +
> +                                     (ep->ss_ep_comp.bmAttributes & 0x3);



> +                             int burst = ep->ss_ep_comp.bMaxBurst + 1;
> +                             psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> +                             psize = psize * mult * burst;

Shouldn't you use ep->ss_ep_comp.wBytesPerInterval instead ?

> +                             uvc_trace(UVC_TRACE_VIDEO,
> +                                             "mult:%d burst:%d psize:%d\n",
> +                                             mult, burst, psize);
> +                             if (psize >= bandwidth && psize <= best_psize) {
> +                                     altsetting = i;
> +                                     best_psize = psize;
> +                                     best_ep = ep;
> +                             }
> +
>                       }
>               }

-- 
Regards,

Laurent Pinchart

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