GPU/SW: Replace event with semaphore

src/core/gpu_backend.cpp

@@ -200,8 +200,7 @@ void GPUBackend::Sync(bool allow_sleep)
   PushCommand(cmd);
   WakeGPUThread();
 
-  m_sync_event.Wait();
-  m_sync_event.Reset();
+  m_sync_semaphore.Wait();
 }
 
 void GPUBackend::RunGPULoop()
@@ -252,7 +251,7 @@ void GPUBackend::RunGPULoop()
         case GPUBackendCommandType::Sync:
         {
           DebugAssert(read_ptr == write_ptr);
-          m_sync_event.Signal();
+          m_sync_semaphore.Post();
           allow_sleep = static_cast<const GPUBackendSyncCommand*>(cmd)->allow_sleep;
         }
         break;

src/core/gpu_backend.h

@@ -66,7 +66,7 @@ protected:
 
   Common::Rectangle<u32> m_drawing_area{};
 
-  Common::Event m_sync_event;
+  Threading::KernelSemaphore m_sync_semaphore;
   std::atomic_bool m_gpu_thread_sleeping{false};
   std::atomic_bool m_gpu_loop_done{false};
   Threading::Thread m_gpu_thread;