+ boost::shared_ptr<AutomationList> al = boost::dynamic_pointer_cast<AutomationList> (_list);
+ const framepos_t pos = _session.transport_frame();
+ bool to_list;
+ double old_value;
+
+ /* We cannot use ::get_value() here since that is virtual, and intended
+ to return a scalar value that in some way reflects the state of the
+ control (with semantics defined by the control itself, since it's
+ internal state may be more complex than can be fully represented by
+ a single scalar).
+
+ This method's only job is to set the "user_double()" value of the
+ underlying Evoral::Control object, and so we should compare the new
+ value we're being given to the current user_double().
+
+ Unless ... we're doing automation playback, in which case the
+ current effective value of the control (used to determine if
+ anything has changed) is the one derived from the automation event
+ list.
+ */
+
+ if (!al) {
+ to_list = false;
+ old_value = Control::user_double();
+ } else {
+ if (al->automation_write ()) {
+ to_list = true;
+ old_value = Control::user_double ();
+ } else if (al->automation_playback()) {
+ to_list = false;
+ old_value = al->eval (pos);
+ } else {
+ to_list = false;
+ old_value = Control::user_double ();
+ }
+ }
+
+ Control::set_double (value, pos, to_list);