gui/input: only init and quit SDL once for all instances

Calling SDL_Quit while two handlers are active can cause controllers to disconnect

rpcs3/Input/sdl_pad_handler.cpp

@@ -5,8 +5,13 @@
 #include "Emu/system_utils.hpp"
 #include "Emu/system_config.h"
 
+#include <mutex>
+
 LOG_CHANNEL(sdl_log, "SDL");
 
+std::mutex g_sdl_mutex;
+u32 g_sdl_handler_count = 0;
+
 constexpr u32 rumble_duration_ms = 500; // Some high number to keep rumble updates at a minimum.
 constexpr u32 rumble_refresh_ms = rumble_duration_ms - 100; // We need to keep updating the rumble. Choose a refresh timeout that is unlikely to run into missed rumble updates.
 
@@ -83,7 +88,13 @@ sdl_pad_handler::~sdl_pad_handler()
 		}
 	}
 
+	// Only quit SDL if this is the last instance of the handler. SDL uses a global state internally...
+	std::lock_guard lock(g_sdl_mutex);
+	if (g_sdl_handler_count > 0 && --g_sdl_handler_count == 0)
+	{
+		sdl_log.notice("Quitting SDL ...");
 		SDL_Quit();
+	}
 }
 
 void sdl_pad_handler::init_config(cfg_pad* cfg)
@@ -146,6 +157,13 @@ bool sdl_pad_handler::Init()
 	if (m_is_init)
 		return true;
 
+	std::lock_guard lock(g_sdl_mutex);
+
+	// Only init SDL if this is the first instance of the handler. SDL uses a global state internally...
+	if (g_sdl_handler_count++ == 0)
+	{
+		sdl_log.notice("Initializing SDL ...");
+
 		// Set non-dynamic hints before SDL_Init
 		if (!SDL_SetHint(SDL_HINT_JOYSTICK_THREAD, "1"))
 		{
@@ -218,6 +236,7 @@ bool sdl_pad_handler::Init()
 				break;
 			}
 		}, nullptr);
+	}
 
 	if (g_cfg.io.load_sdl_mappings)
 	{