[media] v4l2-ctrls: compare values only once

When setting a control the control's new value is compared to the current
value twice: once by new_to_cur(), once by cluster_changed(). Not a big
deal when dealing with simple values, but it can be a problem when dealing
with compound types or arrays. So fix this: cluster_changed() sets the
has_changed flag, which is used by new_to_cur() instead of having to do
another compare.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index ddd9fdf1ac1a..a38bd55909b2 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -96,6 +96,8 @@ typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
   * @is_new:    Set when the user specified a new value for this control. It
   *             is also set when called from v4l2_ctrl_handler_setup. Drivers
   *             should never set this flag.
+  * @has_changed: Set when the current value differs from the new value. Drivers
+  *             should never use this flag.
   * @is_private: If set, then this control is private to its handler and it
   *             will not be added to any other handlers. Drivers can set
   *             this flag.
@@ -158,6 +160,7 @@ struct v4l2_ctrl {
         unsigned int done:1;
 
         unsigned int is_new:1;
+        unsigned int has_changed:1;
         unsigned int is_private:1;
         unsigned int is_auto:1;
         unsigned int is_int:1;