Hi John
Maybe you could add a function like
static bool is_relative_ptz_ctr(__u32 id)
{
switch (xctrl->id) {
case V4L2_CID_ZOOM_CONTINUOUS:
case V4L2_CID_PAN_SPEED:
case V4L2_CID_TILT_SPEED:
return true;
}
return false;
}
to figure out if a control is relative or not, and avoid code duplication.
On Fri, 29 Mar 2024 at 00:18, John Bauer via B4 Relay
<devnull+johnebgood.securitylive.com@xxxxxxxxxx> wrote:
>
> From: John Bauer <johnebgood@xxxxxxxxxxxxxxxx>
>
> The minimum UVC control value for the relative pan/tilt/zoom speeds
> cannot be probed as the implementation condenses the pan and tilt
> direction and speed into two 16 bit values. The minimum cannot be
> set at probe time because it is probed first and the maximum is not
> yet known. With this fix if a relative speed control is queried
> or set the minimum is set and checked based on the additive inverse of
> the maximum at that time.
>
> Signed-off-by: John Bauer <johnebgood@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 37 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index e59a463c2761..b389ab3ee05d 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1322,9 +1322,25 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> break;
> }
>
> - if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MIN)
> - v4l2_ctrl->minimum = mapping->get(mapping, UVC_GET_MIN,
> - uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN));
> + if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MIN) {
> + switch (v4l2_ctrl->id) {
> + case V4L2_CID_ZOOM_CONTINUOUS:
> + case V4L2_CID_PAN_SPEED:
> + case V4L2_CID_TILT_SPEED:
> + /*
> + * For the relative speed implementation the minimum
> + * value cannot be probed so it becomes the additive
> + * inverse of maximum.
> + */
> + v4l2_ctrl->minimum = -1 * mapping->get(mapping, UVC_GET_MAX,
> + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
> + break;
> + default:
> + v4l2_ctrl->minimum = mapping->get(mapping, UVC_GET_MIN,
> + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN));
> + break;
> + }
> + }
>
> if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MAX)
> v4l2_ctrl->maximum = mapping->get(mapping, UVC_GET_MAX,
> @@ -1914,6 +1930,21 @@ int uvc_ctrl_set(struct uvc_fh *handle,
> uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN));
> max = mapping->get(mapping, UVC_GET_MAX,
> uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
> +
> + /*
> + * For the relative speed implementation the minimum
> + * value cannot be probed so it becomes the additive
> + * inverse of maximum.
> + */
> + switch (xctrl->id) {
> + case V4L2_CID_ZOOM_CONTINUOUS:
> + case V4L2_CID_PAN_SPEED:
> + case V4L2_CID_TILT_SPEED:
> + min = max * -1;
> + default:
> + break;
> + }
> +
> step = mapping->get(mapping, UVC_GET_RES,
> uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES));
> if (step == 0)
>
> --
> 2.34.1
>
>
--
Ricardo Ribalda
