From ea9690d72b1c51371b488bd93655d9023991272b Mon Sep 17 00:00:00 2001
From: Ken Cooke <ken@highfidelity.io>
Date: Mon, 6 May 2019 10:46:54 -0700
Subject: [PATCH 1/3] Disable MIDI rescan after devicechange, to avoid deadlock

---
 interface/src/Application.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 59f4934dca..6b956e7f55 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -557,7 +557,10 @@ public:
                     return true;
                 }
             }
-
+            // Attempting to close MIDI interfaces of a hot-unplugged device can result in audio-driver deadlock.
+            // Detecting MIDI devices that have been added/removed after starting Inteface has been disabled.
+            // https://support.microsoft.com/en-us/help/4460006/midi-device-app-hangs-when-former-midi-api-is-used
+#if 0
             if (message->message == WM_DEVICECHANGE) {
                 const float MIN_DELTA_SECONDS = 2.0f; // de-bounce signal
                 static float lastTriggerTime = 0.0f;
@@ -567,6 +570,7 @@ public:
                     Midi::USBchanged();                // re-scan the MIDI bus
                 }
             }
+#endif
         }
         return false;
     }

From f133ab65e4adb138413c2ecee84932fc158dff45 Mon Sep 17 00:00:00 2001
From: Ken Cooke <ken@highfidelity.io>
Date: Mon, 6 May 2019 10:48:53 -0700
Subject: [PATCH 2/3] MIDI bugfix

---
 libraries/midi/src/Midi.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/midi/src/Midi.cpp b/libraries/midi/src/Midi.cpp
index 1f190111f2..06c370761e 100644
--- a/libraries/midi/src/Midi.cpp
+++ b/libraries/midi/src/Midi.cpp
@@ -206,7 +206,7 @@ void Midi::MidiSetup() {
 
     MIDIOUTCAPS outcaps;
     for (unsigned int i = 0; i < midiOutGetNumDevs(); i++) {
-        midiOutGetDevCaps(i, &outcaps, sizeof(MIDIINCAPS));
+        midiOutGetDevCaps(i, &outcaps, sizeof(MIDIOUTCAPS));
 
         bool found = false;
         for (int j = 0; j < midiOutExclude.size(); j++) {

From 408fb56d57d5b89f3351e99ee2f2554aebb176f1 Mon Sep 17 00:00:00 2001
From: Ken Cooke <ken@highfidelity.io>
Date: Mon, 6 May 2019 10:53:58 -0700
Subject: [PATCH 3/3] MIDI error checking

---
 libraries/midi/src/Midi.cpp | 51 ++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/libraries/midi/src/Midi.cpp b/libraries/midi/src/Midi.cpp
index 06c370761e..1b58148e98 100644
--- a/libraries/midi/src/Midi.cpp
+++ b/libraries/midi/src/Midi.cpp
@@ -187,38 +187,43 @@ void Midi::MidiSetup() {
 
     MIDIINCAPS incaps;
     for (unsigned int i = 0; i < midiInGetNumDevs(); i++) {
-        midiInGetDevCaps(i, &incaps, sizeof(MIDIINCAPS));
+        if (MMSYSERR_NOERROR == midiInGetDevCaps(i, &incaps, sizeof(MIDIINCAPS))) {
 
-        bool found = false;
-        for (int j = 0; j < midiInExclude.size(); j++) {
-            if (midiInExclude[j].toStdString().compare(incaps.szPname) == 0) {
-                found = true;
-                break;
+            bool found = false;
+            for (int j = 0; j < midiInExclude.size(); j++) {
+                if (midiInExclude[j].toStdString().compare(incaps.szPname) == 0) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) {        // EXCLUDE AN INPUT BY NAME
+                HMIDIIN tmphin;
+                if (MMSYSERR_NOERROR == midiInOpen(&tmphin, i, (DWORD_PTR)MidiInProc, NULL, CALLBACK_FUNCTION)) {
+                    if (MMSYSERR_NOERROR == midiInStart(tmphin)) {
+                        midihin.push_back(tmphin);
+                    }
+                }
             }
-        }
-        if (!found) {        // EXCLUDE AN INPUT BY NAME
-            HMIDIIN tmphin;
-            midiInOpen(&tmphin, i, (DWORD_PTR)MidiInProc, NULL, CALLBACK_FUNCTION);
-            midiInStart(tmphin);
-            midihin.push_back(tmphin);
         }
     }
 
     MIDIOUTCAPS outcaps;
     for (unsigned int i = 0; i < midiOutGetNumDevs(); i++) {
-        midiOutGetDevCaps(i, &outcaps, sizeof(MIDIOUTCAPS));
+        if (MMSYSERR_NOERROR == midiOutGetDevCaps(i, &outcaps, sizeof(MIDIOUTCAPS))) {
 
-        bool found = false;
-        for (int j = 0; j < midiOutExclude.size(); j++) {
-            if (midiOutExclude[j].toStdString().compare(outcaps.szPname) == 0) {
-                found = true;
-                break;
+            bool found = false;
+            for (int j = 0; j < midiOutExclude.size(); j++) {
+                if (midiOutExclude[j].toStdString().compare(outcaps.szPname) == 0) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) {        // EXCLUDE AN OUTPUT BY NAME
+                HMIDIOUT tmphout;
+                if (MMSYSERR_NOERROR == midiOutOpen(&tmphout, i, (DWORD_PTR)MidiOutProc, NULL, CALLBACK_FUNCTION)) {
+                    midihout.push_back(tmphout);
+                }
             }
-        }
-        if (!found) {        // EXCLUDE AN OUTPUT BY NAME
-            HMIDIOUT tmphout;
-            midiOutOpen(&tmphout, i, (DWORD_PTR)MidiOutProc, NULL, CALLBACK_FUNCTION);
-            midihout.push_back(tmphout);
         }
     }