From 86d818e4b940e812bbd80b5f7c51b3996fd58ae0 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Fri, 21 Jul 2023 00:38:29 +0200
Subject: [PATCH] Revert VST3 kMono arrangement experiment #9418

Apparently kMono is not a flag and implies connection of the first port

This reverts commit 8aebfc45dc0d275aaf0fd8125cb6b918d5d0d401.
and  2698b23f824fdce28934dd30850906e02352e396.
---
 libs/ardour/ardour/vst3_plugin.h |  3 +++
 libs/ardour/vst3_plugin.cc       | 19 +++++++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/libs/ardour/ardour/vst3_plugin.h b/libs/ardour/ardour/vst3_plugin.h
index 3cad78d02d..4e270ba03c 100644
--- a/libs/ardour/ardour/vst3_plugin.h
+++ b/libs/ardour/ardour/vst3_plugin.h
@@ -332,6 +332,9 @@ private:
 	int _n_midi_inputs;
 	int _n_midi_outputs;
 	int _n_factory_presets;
+
+	/* work around UADx plugin crash */
+	bool _no_kMono;
 };
 
 } // namespace Steinberg
diff --git a/libs/ardour/vst3_plugin.cc b/libs/ardour/vst3_plugin.cc
index 5302be3a38..b28ffe4a76 100644
--- a/libs/ardour/vst3_plugin.cc
+++ b/libs/ardour/vst3_plugin.cc
@@ -1161,6 +1161,7 @@ VST3PI::VST3PI (std::shared_ptr<ARDOUR::VST3PluginModule> m, std::string unique_
 	, _owner (0)
 	, _add_to_selection (false)
 	, _n_factory_presets (0)
+	, _no_kMono (false)
 {
 	using namespace std;
 	IPluginFactory* factory = m->factory ();
@@ -1173,6 +1174,16 @@ VST3PI::VST3PI (std::shared_ptr<ARDOUR::VST3PluginModule> m, std::string unique_
 		throw failed_constructor ();
 	}
 
+	PFactoryInfo fi;
+	if (factory->getFactoryInfo (&fi) == kResultTrue) {
+		/* work around issue with UADx VST3s not recognizing
+		 * Vst::SpeakerArr::kMono. (see commit message for details)
+		 */
+		if (0 == strcmp (fi.vendor, "Universal Audio (UADx)")) {
+			_no_kMono = true;
+		}
+	}
+
 #ifndef NDEBUG
 	if (DEBUG_ENABLED (DEBUG::VST3Config)) {
 		char fuid[33];
@@ -2210,8 +2221,8 @@ VST3PI::enable_io (std::vector<bool> const& ins, std::vector<bool> const& outs)
 		}
 		cnt += n_chn;
 		/* special case for Left only == Mono */
-		if (sa == 1 /*Vst::SpeakerArr::kSpeakerL */) {
-			sa |= Vst::SpeakerArr::kMono; /* 1 << 19 */
+		if (sa == 1 /*Vst::SpeakerArr::kSpeakerL */ && !_no_kMono) {
+			sa = Vst::SpeakerArr::kMono; /* 1 << 19 */
 		}
 
 		DEBUG_TRACE (DEBUG::VST3Config, string_compose ("VST3PI::enable_io: activateBus (kAudio, kInput, %1, %2) used-chn: %3 spk-arr: %4\n", sa_in.size (), enable, _bus_info_in[sa_in.size ()].n_used_chn, std::hex, sa));
@@ -2234,8 +2245,8 @@ VST3PI::enable_io (std::vector<bool> const& ins, std::vector<bool> const& outs)
 		}
 		cnt += n_chn;
 		/* special case for Left only == Mono */
-		if (sa == 1 /*Vst::SpeakerArr::kSpeakerL */) {
-			sa |= Vst::SpeakerArr::kMono; /* 1 << 19 */
+		if (sa == 1 /*Vst::SpeakerArr::kSpeakerL */ && !_no_kMono) {
+			sa = Vst::SpeakerArr::kMono; /* 1 << 19 */
 		}
 		DEBUG_TRACE (DEBUG::VST3Config, string_compose ("VST3PI::enable_io: activateBus (kAudio, kOutput, %1, %2) used-chn: %3 spk-arr: %4\n", sa_out.size (), enable, _bus_info_out[sa_out.size ()].n_used_chn, std::hex, sa));
 		_component->activateBus (Vst::kAudio, Vst::kOutput, sa_out.size (), enable);