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

From: John Bauer via B4 Relay
Date: Thu Mar 28 2024 - 19:18:30 EST


From: John Bauer <johnebgood@xxxxxxxxxxxxxxxx>

Made recommended changes from Ricardo. I explored the case where
the minimum could be > 0 but less than the maximum. If this were
to occur the range of -maximum to maximum would still apply correctly
however there would be a range from -min to min that would possibly
not apply. It would be possible to capture the probed minimum and
check against that when setting the controls.

Signed-off-by: John Bauer <johnebgood@xxxxxxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_ctrl.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index b389ab3ee05d..04300a782c81 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1322,6 +1322,10 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
break;
}

+ if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MAX)
+ v4l2_ctrl->maximum = mapping->get(mapping, UVC_GET_MAX,
+ uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
+
if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MIN) {
switch (v4l2_ctrl->id) {
case V4L2_CID_ZOOM_CONTINUOUS:
@@ -1332,8 +1336,7 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
* 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));
+ v4l2_ctrl->minimum = -v4l2_ctrl->maximum;
break;
default:
v4l2_ctrl->minimum = mapping->get(mapping, UVC_GET_MIN,
@@ -1342,10 +1345,6 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
}
}

- if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MAX)
- v4l2_ctrl->maximum = mapping->get(mapping, UVC_GET_MAX,
- uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
-
if (ctrl->info.flags & UVC_CTRL_FLAG_GET_RES)
v4l2_ctrl->step = mapping->get(mapping, UVC_GET_RES,
uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES));
@@ -1940,7 +1939,7 @@ int uvc_ctrl_set(struct uvc_fh *handle,
case V4L2_CID_ZOOM_CONTINUOUS:
case V4L2_CID_PAN_SPEED:
case V4L2_CID_TILT_SPEED:
- min = max * -1;
+ min = -max;
default:
break;
}

--
2.34.1