On Mon, Oct 10, 2022 at 12:20:00AM +0200, Michael Grzeschik wrote:
> For the userspace it is needed to distinguish between reqeuests for the
> control or streaming interace. The userspace would have to parse the
> configfs to know which interface index it has to compare the ctrl
> requests against, since the interface numbers are not fixed, e.g. for
> composite gadgets.
>
> The kernel has this information when handing over the ctrl request to
> the userspace. This patch adds a variable to indicate if the ctrl
> request was meant for the streaming interface.
>
> Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
> ---
> drivers/usb/gadget/function/f_uvc.c | 6 ++++++
> include/uapi/linux/usb/g_uvc.h | 2 ++
> 2 files changed, 8 insertions(+)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index 6e196e06181ecf..132d47798c0f13 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -228,6 +228,7 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
> struct uvc_device *uvc = to_uvc(f);
> struct v4l2_event v4l2_event;
> struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
> + unsigned int interface = le16_to_cpu(ctrl->wIndex) & 0xff;
>
> if ((ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS) {
> uvcg_info(f, "invalid request type\n");
> @@ -246,6 +247,11 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
> uvc->event_length = le16_to_cpu(ctrl->wLength);
>
> memset(&v4l2_event, 0, sizeof(v4l2_event));
> +
> + /* check for the interface number, so the userspace doesn't have to */
> + if (interface == uvc->streaming_intf)
> + uvc_event->ctrlreq_streaming = 1;
> +
> v4l2_event.type = UVC_EVENT_SETUP;
> memcpy(&uvc_event->req, ctrl, sizeof(uvc_event->req));
> v4l2_event_queue(&uvc->vdev, &v4l2_event);
> diff --git a/include/uapi/linux/usb/g_uvc.h b/include/uapi/linux/usb/g_uvc.h
> index 652f169a019e7d..8711d706e5bfb0 100644
> --- a/include/uapi/linux/usb/g_uvc.h
> +++ b/include/uapi/linux/usb/g_uvc.h
> @@ -27,6 +27,8 @@ struct uvc_request_data {
> };
>
> struct uvc_event {
> + /* indicate if the ctrl request is for the streaming interface */
> + __u8 ctrlreq_streaming;
How can you change a public api structure like this without breaking all
existing userspace code?
thanks,
greg k-h
