Fix non-summon of butler when a track that needs it is followed by a track that does not (in the single-process-thread-CPU case). Should fix #4677.

git-svn-id: svn://localhost/ardour2/branches/3.0@11391 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 20 insertions, 2 deletions

diff --git a/libs/ardour/session_process.cc b/libs/ardour/session_process.cc
index d79e2b2c67..db45143259 100644
--- a/libs/ardour/session_process.cc
+++ b/libs/ardour/session_process.cc
@@ -146,6 +146,9 @@ Session::no_roll (pframes_t nframes)
 	return ret;
 }
 
+/** @param need_butler to be set to true by this method if it needs the butler,
+ *  otherwise it can be left alone or set to false.
+ */
 int
 Session::process_routes (pframes_t nframes, bool& need_butler)
 {
@@ -175,16 +178,25 @@ Session::process_routes (pframes_t nframes, bool& need_butler)
 
 			(*i)->set_pending_declick (declick);
 
-			if ((ret = (*i)->roll (nframes, start_frame, end_frame, declick, need_butler)) < 0) {
+			bool b = false;
+
+			if ((ret = (*i)->roll (nframes, start_frame, end_frame, declick, b)) < 0) {
 				stop_transport ();
 				return -1;
 			}
+
+			if (b) {
+				need_butler = true;
+			}
 		}
 	}
 
 	return 0;
 }
 
+/** @param need_butler to be set to true by this method if it needs the butler,
+ *  otherwise it must be left alone.
+ */
 int
 Session::silent_process_routes (pframes_t nframes, bool& need_butler)
 {
@@ -204,10 +216,16 @@ Session::silent_process_routes (pframes_t nframes, bool& need_butler)
 				continue;
 			}
 
-			if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, need_butler)) < 0) {
+			bool b = false;
+
+			if ((ret = (*i)->silent_roll (nframes, start_frame, end_frame, b)) < 0) {
 				stop_transport ();
 				return -1;
 			}
+
+			if (b) {
+				need_butler = true;
+			}
 		}
 	}