avoid crashing in a wierd case (possibly a race) in Mackie support

git-svn-id: svn://localhost/ardour2/branches/3.0@13749 d708f5d6-7413-0410-9779-e7cbd77b26cf

diff --git a/libs/surfaces/mackie/mackie_control_protocol.cc b/libs/surfaces/mackie/mackie_control_protocol.cc
index 3791252ade0bf651599db8e472e6e206ca26b168..911d2e56aaa75a5cde12764752e4e1bc79b688d7 100644 (file)
--- a/libs/surfaces/mackie/mackie_control_protocol.cc
+++ b/libs/surfaces/mackie/mackie_control_protocol.cc
@@ -524,6 +524,10 @@ MackieControlProtocol::update_surfaces()
 void
 MackieControlProtocol::initialize()
 {
+       if (surfaces.empty()) {
+               return;
+       }
+
        if (!surfaces.front()->active ()) {
                return;
        }