Re: [PATCH] media: uvcvideo: Undup use uvc_endpoint_max_bpi() code

[Ricardo Ribalda]

Dear stable



On Mon, 23 Mar 2026 at 14:03, Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote:
>
> [ Upstream commit 5b9c75c794ce041e6e00789efef75d71915c4f4c ]
>
> Replace manual decoding of psize in uvc_parse_streaming(), with the code
> from uvc_endpoint_max_bpi(). It also handles usb3 devices.
>
> Cc: stable@xxxxxxxxxxxxxxx # v5.4+
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> ---
> The commit: 9764401bf6f8 ("media: uvcvideo: Fix bandwidth issue for Alcor
> camera"), which has been backported to 5.4+, depends on this patch.
>
> Without it, cameras connected to USB3.0 will stop working properly,
> because the bandwidth quirk will be applied wrongly.
>
> Please help adding this patch to 5.4, 5.10 and 5.15.

Is there any update on this?

Regards!


>
> Thanks!
> ---
>  drivers/media/usb/uvc/uvc_driver.c | 4 +---
>  drivers/media/usb/uvc/uvc_video.c  | 3 +--
>  drivers/media/usb/uvc/uvcvideo.h   | 1 +
>  3 files changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 858fc5b26a5e..4ee187a503b8 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -1007,9 +1007,7 @@ static int uvc_parse_streaming(struct uvc_device *dev,
>                                 streaming->header.bEndpointAddress);
>                 if (ep == NULL)
>                         continue;
> -
> -               psize = le16_to_cpu(ep->desc.wMaxPacketSize);
> -               psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
> +               psize = uvc_endpoint_max_bpi(dev->udev, ep);
>                 if (psize > streaming->maxpsize)
>                         streaming->maxpsize = psize;
>         }
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index f868a13280a1..fb69d534e299 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -1797,8 +1797,7 @@ static void uvc_video_stop_transfer(struct uvc_streaming *stream,
>  /*
>   * Compute the maximum number of bytes per interval for an endpoint.
>   */
> -static unsigned int uvc_endpoint_max_bpi(struct usb_device *dev,
> -                                        struct usb_host_endpoint *ep)
> +u16 uvc_endpoint_max_bpi(struct usb_device *dev, struct usb_host_endpoint *ep)
>  {
>         u16 psize;
>         u16 mult;
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 95af1591f105..f5bc9fa2c385 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -920,6 +920,7 @@ void uvc_simplify_fraction(u32 *numerator, u32 *denominator,
>  u32 uvc_fraction_to_interval(u32 numerator, u32 denominator);
>  struct usb_host_endpoint *uvc_find_endpoint(struct usb_host_interface *alts,
>                                             u8 epaddr);
> +u16 uvc_endpoint_max_bpi(struct usb_device *dev, struct usb_host_endpoint *ep);
>
>  /* Quirks support */
>  void uvc_video_decode_isight(struct uvc_urb *uvc_urb,
>
> ---
> base-commit: 91d48252ad4b17577cf8cc8d3e1353402e4da8f1
> change-id: 20260323-uvc-backport-bpi-68368ef14173
>
> Best regards,
> --
> Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
>


-- 
Ricardo Ribalda