small optimization, read-only buffer suffices here.

diff --git a/libs/ardour/io.cc b/libs/ardour/io.cc
index 9fa6c7085d1907afafda29037b591cedc7672cb1..79ee78d8a57e6a5b552baa01ce4ba55d3ce13b10 100644 (file)
--- a/libs/ardour/io.cc
+++ b/libs/ardour/io.cc
@@ -1674,7 +1674,7 @@ IO::collect_input (BufferSet& bufs, pframes_t nframes, ChanCount offset)
                }
 
                for ( ; i != _ports.end(*t); ++i, ++b) {
-                       Buffer& bb (i->get_buffer (nframes));
+                       const Buffer& bb (i->get_buffer (nframes));
                        b->read_from (bb, nframes);
                }
        }