Hi,
On 14-Nov-24 8:10 PM, Ricardo Ribalda wrote:
> From: Yunke Cao <yunkec@xxxxxxxxxx>
>
> This patch adds support for compound controls. This is required to
> support controls that cannot be represented with a s64 data, such as the
> Region of Interest.
>
> Signed-off-by: Yunke Cao <yunkec@xxxxxxxxxx>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 224 ++++++++++++++++++++++++++++++++-------
> drivers/media/usb/uvc/uvcvideo.h | 5 +
> 2 files changed, 192 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 893d12cd3f90..e51cd0a2228a 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
<snip>
> @@ -1971,19 +2009,59 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
> return ret;
> }
>
> -int uvc_ctrl_get(struct uvc_video_chain *chain, u32 which,
> - struct v4l2_ext_control *xctrl)
> +static int uvc_mapping_get_xctrl_compound(struct uvc_video_chain *chain,
> + struct uvc_control *ctrl,
> + struct uvc_control_mapping *mapping,
> + u32 which,
> + struct v4l2_ext_control *xctrl)
> {
> - struct uvc_control *ctrl;
> - struct uvc_control_mapping *mapping;
> -
> - if (__uvc_query_v4l2_class(chain, xctrl->id, 0) >= 0)
> - return -EACCES;
> + u8 *data __free(kfree) = NULL;
> + size_t size;
> + u8 query;
> + int ret;
> + int id;
>
> - ctrl = uvc_find_control(chain, xctrl->id, &mapping);
> - if (ctrl == NULL)
> + switch (which) {
> + case V4L2_CTRL_WHICH_CUR_VAL:
> + ret = __uvc_ctrl_load_cur(chain, ctrl);
> + if (ret < 0)
> + return ret;
> + id = UVC_CTRL_DATA_CURRENT;
> + query = UVC_GET_CUR;
> + break;
> + case V4L2_CTRL_WHICH_DEF_VAL:
> + ret = uvc_ctrl_populate_cache(chain, ctrl);
> + if (ret < 0)
> + return ret;
> + id = UVC_CTRL_DATA_DEF;
> + query = UVC_GET_DEF;
> + break;
> + default:
> return -EINVAL;
> + }
> +
> + size = DIV_ROUND_UP(mapping->size, 8);
> + if (xctrl->size < size) {
> + xctrl->size = size;
> + return -ENOSPC;
> + }
> +
> + data = kmalloc(size, GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + ret = mapping->get(mapping, query, uvc_ctrl_data(ctrl, id), size, data);
> + if (ret < 0)
> + return ret;
> +
> + return copy_to_user(xctrl->ptr, data, size) ? -EFAULT : 0;
> +}
While reviewing "[PATCH v15 14/19] media: uvcvideo: Use the camera to clamp compound controls"
I realized that this copy_to_user() is somewhat unexpected. Normally we let the v4l2 core
ioctl wrapper take care of this.
Since there is no room in struct v4l2_ext_control to store the data I guess this is ok,
but IMHO this does at least need a comment explaining how this is a special case.
Regards,
Hans
