2024-03-28 23:18:35

by John Bauer via B4 Relay

Subject: [PATCH 1/2] media: uvcvideo: UVC minimum relative pan/tilt/zoom speed fix

From: John Bauer <[email protected]>

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 <[email protected]>
---
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

2024-04-02 11:54:23

by Ricardo Ribalda

Subject: Re: [PATCH 1/2] media: uvcvideo: UVC minimum relative pan/tilt/zoom speed fix

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
<[email protected]> wrote:
>
> From: John Bauer <[email protected]>
>
> 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 <[email protected]>
> ---
> 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