From 2932337a32eeea40ab9ac33c505e8dc603f45624 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Tue, 7 Apr 2020 04:06:02 +0200
Subject: [PATCH] Fix ambiguous latency check

Only compare playback latency, delaylines in tracks do not
push back the capture latency to the source.
The delayline on tracks sits in between disk-writer and disk-reader,
delaying input to align with the disk-reader.

Furthermore tracks may be connected to different inputs,
even though those inputs are usually from the same hardware
device, capture latency of those ports can differ.
---
 libs/ardour/port_manager.cc | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/libs/ardour/port_manager.cc b/libs/ardour/port_manager.cc
index 00648dda8b..841a04a4f5 100644
--- a/libs/ardour/port_manager.cc
+++ b/libs/ardour/port_manager.cc
@@ -1380,19 +1380,19 @@ PortManager::check_for_amibiguous_latency (bool log) const
 {
 	bool rv = false;
 	boost::shared_ptr<Ports> plist = ports.reader();
-	for (Ports::iterator p = plist->begin(); p != plist->end(); ++p) {
-		for (int c = 0; c < 1; ++c) {
-			LatencyRange range;
-			p->second->get_connected_latency_range (range, c ? true : false);
-			if (range.min != range.max) {
-				if (log) {
-					warning << string_compose(_("PortEngine: ambiguous %1 latency for port '%2' (%3, %4)"),
-							(c ? "playback" : "capture"), p->second->name(), range.min, range.max)
-					        << endmsg;
-					rv = true;
-				} else {
+	for (Ports::iterator pi = plist->begin(); pi != plist->end(); ++pi) {
+		boost::shared_ptr<Port> const& p (pi->second);
+		if (! p->sends_output ()) {
+			continue;
+		}
+		LatencyRange range;
+		p->get_connected_latency_range (range, true);
+		if (range.min != range.max) {
+			if (log) {
+				warning << string_compose(_("Ambiguous latency for port '%1' (%2, %3)"), p->name(), range.min, range.max) << endmsg;
+				rv = true;
+			} else {
 				return true;
-				}
 			}
 		}
 	}