Use separate libusb contexts to avoid thread safety issues

Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp

@@ -28,7 +28,6 @@
 #include "Core/Core.h"
 #include "Core/HW/Memmap.h"
 #include "Core/IOS/Device.h"
-#include "Core/LibusbUtils.h"
 #include "VideoCommon/OnScreenDisplay.h"
 
 namespace IOS::HLE::Device
@@ -75,11 +74,10 @@ BluetoothReal::~BluetoothReal()
 
 IPCCommandResult BluetoothReal::Open(const OpenRequest& request)
 {
-  auto& context = LibusbUtils::GetContext();
-  if (!context.IsValid())
+  if (!m_context.IsValid())
     return GetDefaultReply(IPC_EACCES);
 
-  context.GetDeviceList([this](libusb_device* device) {
+  m_context.GetDeviceList([this](libusb_device* device) {
     libusb_device_descriptor device_descriptor;
     libusb_get_device_descriptor(device, &device_descriptor);
     auto config_descriptor = LibusbUtils::MakeConfigDescriptor(device);
@@ -594,8 +592,7 @@ void BluetoothReal::HandleCtrlTransfer(libusb_transfer* tr)
   }
   const auto& command = m_current_transfers.at(tr).command;
   command->FillBuffer(libusb_control_transfer_get_data(tr), tr->actual_length);
-  m_ios.EnqueueIPCReply(command->ios_request, tr->actual_length, 0,
-                        CoreTiming::FromThread::NON_CPU);
+  m_ios.EnqueueIPCReply(command->ios_request, tr->actual_length, 0, CoreTiming::FromThread::ANY);
   m_current_transfers.erase(tr);
 }
 
@@ -643,8 +640,7 @@ void BluetoothReal::HandleBulkOrIntrTransfer(libusb_transfer* tr)
 
   const auto& command = m_current_transfers.at(tr).command;
   command->FillBuffer(tr->buffer, tr->actual_length);
-  m_ios.EnqueueIPCReply(command->ios_request, tr->actual_length, 0,
-                        CoreTiming::FromThread::NON_CPU);
+  m_ios.EnqueueIPCReply(command->ios_request, tr->actual_length, 0, CoreTiming::FromThread::ANY);
   m_current_transfers.erase(tr);
 }
 }  // namespace IOS::HLE::Device

Source/Core/Core/IOS/USB/Bluetooth/BTReal.h

@@ -19,6 +19,7 @@
 #include "Core/IOS/USB/Bluetooth/BTBase.h"
 #include "Core/IOS/USB/Bluetooth/hci.h"
 #include "Core/IOS/USB/USBV0.h"
+#include "Core/LibusbUtils.h"
 
 class PointerWrap;
 struct libusb_device;
@@ -70,6 +71,7 @@ class BluetoothReal final : public BluetoothBase
   std::atomic<SyncButtonState> m_sync_button_state{SyncButtonState::Unpressed};
   Common::Timer m_sync_button_held_timer;
 
+  LibusbUtils::Context m_context;
   libusb_device* m_device = nullptr;
   libusb_device_handle* m_handle = nullptr;
 

Source/Core/Core/IOS/USB/Host.cpp

@@ -24,7 +24,6 @@
 #include "Core/Core.h"
 #include "Core/IOS/USB/Common.h"
 #include "Core/IOS/USB/LibusbDevice.h"
-#include "Core/LibusbUtils.h"
 
 namespace IOS::HLE::Device
 {
@@ -121,10 +120,9 @@ bool USBHost::AddNewDevices(std::set<u64>& new_devices, DeviceChangeHooks& hooks
   if (SConfig::GetInstance().m_usb_passthrough_devices.empty())
     return true;
 
-  auto& context = LibusbUtils::GetContext();
-  if (context.IsValid())
+  if (m_context.IsValid())
   {
-    context.GetDeviceList([&](libusb_device* device) {
+    m_context.GetDeviceList([&](libusb_device* device) {
       libusb_device_descriptor descriptor;
       libusb_get_device_descriptor(device, &descriptor);
       const std::pair<u16, u16> vid_pid = {descriptor.idVendor, descriptor.idProduct};

Source/Core/Core/IOS/USB/Host.h

@@ -20,6 +20,7 @@
 #include "Core/IOS/Device.h"
 #include "Core/IOS/IOS.h"
 #include "Core/IOS/USB/Common.h"
+#include "Core/LibusbUtils.h"
 
 class PointerWrap;
 
@@ -71,5 +72,6 @@ class USBHost : public Device
   std::thread m_scan_thread;
   Common::Event m_first_scan_complete_event;
   bool m_has_initialised = false;
+  LibusbUtils::Context m_context;
 };
 }  // namespace IOS::HLE::Device

Source/Core/Core/LibusbUtils.cpp

@@ -109,12 +109,6 @@ bool Context::GetDeviceList(GetDeviceListCallback callback)
   return m_impl->GetDeviceList(std::move(callback));
 }
 
-Context& GetContext()
-{
-  static Context s_context;
-  return s_context;
-}
-
 ConfigDescriptor MakeConfigDescriptor(libusb_device* device, u8 config_num)
 {
 #if defined(__LIBUSB__)

Source/Core/Core/LibusbUtils.h

@@ -38,11 +38,6 @@ class Context
   std::unique_ptr<Impl> m_impl;
 };
 
-// Use this to get a libusb context. Do *not* use any other context
-// because some libusb backends such as UsbDk only work properly with a single context.
-// Additionally, device lists must be retrieved using GetDeviceList for thread safety reasons.
-Context& GetContext();
-
 using ConfigDescriptor = UniquePtr<libusb_config_descriptor>;
 ConfigDescriptor MakeConfigDescriptor(libusb_device* device, u8 config_num = 0);
 }  // namespace LibusbUtils

Source/Core/InputCommon/GCAdapter.cpp

@@ -72,6 +72,8 @@ static bool s_libusb_hotplug_enabled = false;
 static libusb_hotplug_callback_handle s_hotplug_handle;
 #endif
 
+static LibusbUtils::Context s_libusb_context;
+
 static u8 s_endpoint_in = 0;
 static u8 s_endpoint_out = 0;
 
@@ -147,7 +149,6 @@ static int HotplugCallback(libusb_context* ctx, libusb_device* dev, libusb_hotpl
 
 static void ScanThreadFunc()
 {
-  auto& context = LibusbUtils::GetContext();
   Common::SetCurrentThreadName("GC Adapter Scanning Thread");
   NOTICE_LOG(SERIALINTERFACE, "GC Adapter scanning thread started");
 
@@ -158,7 +159,7 @@ static void ScanThreadFunc()
   if (s_libusb_hotplug_enabled)
   {
     if (libusb_hotplug_register_callback(
-            context,
+            s_libusb_context,
             (libusb_hotplug_event)(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
                                    LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
             LIBUSB_HOTPLUG_ENUMERATE, 0x057e, 0x0337, LIBUSB_HOTPLUG_MATCH_ANY, HotplugCallback,
@@ -212,7 +213,7 @@ void StartScanThread()
 {
   if (s_adapter_detect_thread_running.IsSet())
     return;
-  if (!LibusbUtils::GetContext().IsValid())
+  if (!s_libusb_context.IsValid())
     return;
   s_adapter_detect_thread_running.Set(true);
   s_adapter_detect_thread = std::thread(ScanThreadFunc);
@@ -240,7 +241,7 @@ static void Setup()
     s_controller_rumble[i] = 0;
   }
 
-  LibusbUtils::GetContext().GetDeviceList([](libusb_device* device) {
+  s_libusb_context.GetDeviceList([](libusb_device* device) {
     if (CheckDeviceAccess(device))
     {
       // Only connect to a single adapter in case the user has multiple connected
@@ -364,8 +365,8 @@ void Shutdown()
 {
   StopScanThread();
 #if defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102
-  if (LibusbUtils::GetContext().IsValid() && s_libusb_hotplug_enabled)
-    libusb_hotplug_deregister_callback(LibusbUtils::GetContext(), s_hotplug_handle);
+  if (s_libusb_context.IsValid() && s_libusb_hotplug_enabled)
+    libusb_hotplug_deregister_callback(s_libusb_context, s_hotplug_handle);
 #endif
   Reset();
 

Source/Core/UICommon/USBUtils.cpp

@@ -35,7 +35,7 @@ std::map<std::pair<u16, u16>, std::string> GetInsertedDevices()
   std::map<std::pair<u16, u16>, std::string> devices;
 
 #ifdef __LIBUSB__
-  auto& context = LibusbUtils::GetContext();
+  LibusbUtils::Context context;
   if (!context.IsValid())
     return devices;