[PATCH 2/3] media: uvcvideo: Do not send events for not changed controls

[Ricardo Ribalda <ribalda@chromium.org>]

Only send events for controls that have actually changed.
E.g.: We are changing entities A, B and C. If we get an error while
we change B we do not continue setting C. But the current code sends an
event also for C.

Due to the fact that the controls are grouped by entities, and the user
might group them in different orders, we cannot send the events at the
end, but when we change an entity.

Cc: stable@kernel.org
Fixes: b4012002f3a3 ("[media] uvcvideo: Add support for control events")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 7e2fc97c9f43..9496ac970267 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1669,7 +1669,9 @@ static bool uvc_ctrl_xctrls_has_control(const struct v4l2_ext_control *xctrls,
 }
 
 static void uvc_ctrl_send_events(struct uvc_fh *handle,
-	const struct v4l2_ext_control *xctrls, unsigned int xctrls_count)
+				 struct uvc_entity *entity,
+				 const struct v4l2_ext_control *xctrls,
+				 unsigned int xctrls_count)
 {
 	struct uvc_control_mapping *mapping;
 	struct uvc_control *ctrl;
@@ -1680,6 +1682,9 @@ static void uvc_ctrl_send_events(struct uvc_fh *handle,
 	for (i = 0; i < xctrls_count; ++i) {
 		ctrl = uvc_find_control(handle->chain, xctrls[i].id, &mapping);
 
+		if (ctrl->entity != entity)
+			continue;
+
 		if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
 			/* Notification will be sent from an Interrupt event. */
 			continue;
@@ -1911,11 +1916,12 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
 					uvc_ctrl_find_ctrl_idx(entity, ctrls,
 							       err_ctrl);
 			goto done;
+		} else if (ret > 0 && !rollback) {
+			uvc_ctrl_send_events(handle, entity,
+					     ctrls->controls, ctrls->count);
 		}
 	}
 
-	if (!rollback)
-		uvc_ctrl_send_events(handle, ctrls->controls, ctrls->count);
 done:
 	mutex_unlock(&chain->ctrl_mutex);
 	return ret < 0 ? ret : 0;

-- 
2.47.0.338.g60cca15819-goog