From 5344f5ca0fefa9bd08f4231848a3e92f873538b4 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <carl@carlh.net>
Date: Sat, 10 Dec 2011 14:03:37 +0000
Subject: [PATCH] Don't try to process_input() if an IO has no ports; fixes
 #4546.

git-svn-id: svn://localhost/ardour2/branches/3.0@10965 d708f5d6-7413-0410-9779-e7cbd77b26cf
---
 libs/ardour/io.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libs/ardour/io.cc b/libs/ardour/io.cc
index c5f0c7361d..24bc587c0d 100644
--- a/libs/ardour/io.cc
+++ b/libs/ardour/io.cc
@@ -1554,6 +1554,11 @@ IO::process_input (boost::shared_ptr<Processor> proc, framepos_t start_frame, fr
 {
 	/* don't read the data into new buffers - just use the port buffers directly */
 
+	if (n_ports().n_total() == 0) {
+		/* We have no ports, so nothing to process */
+		return;
+	}
+
 	_buffers.get_jack_port_addresses (_ports, nframes);
 	proc->run (_buffers, start_frame, end_frame, nframes, true);
 }