From f10e2a0db6a3d2cd2b504774a64915092e01af60 Mon Sep 17 00:00:00 2001
From: Vlad Firoiu <vladfi2@gmail.com>
Date: Wed, 22 May 2024 08:57:04 -0400
Subject: [PATCH] Wait for inputs until all PipeDevices have been flushed in
 blocking mode.

---
 .../ControllerInterface/ControllerInterface.cpp           | 4 ++++
 .../Core/InputCommon/ControllerInterface/Pipes/Pipes.cpp  | 8 +++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
index cfb1a4d6d2..c33945143f 100644
--- a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
@@ -40,6 +40,8 @@
 
 using namespace ciface::ExpressionParser;
 
+extern bool g_needInputForFrame; // from EXI_DeviceSlippi.cpp
+
 namespace
 {
 const ControlState INPUT_DETECT_THRESHOLD = 0.55;
@@ -217,6 +219,8 @@ void ControllerInterface::UpdateInput()
 		std::lock_guard<std::mutex> lk(m_devices_mutex, std::adopt_lock);
 		for (const auto& d : m_devices)
 			d->UpdateInput();
+
+		g_needInputForFrame = false;
 	}
 }
 
diff --git a/Source/Core/InputCommon/ControllerInterface/Pipes/Pipes.cpp b/Source/Core/InputCommon/ControllerInterface/Pipes/Pipes.cpp
index 1e2324fe8d..e3287331f6 100644
--- a/Source/Core/InputCommon/ControllerInterface/Pipes/Pipes.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/Pipes/Pipes.cpp
@@ -164,8 +164,9 @@ s32 PipeDevice::readFromPipe(PIPE_FD file_descriptor, char *in_buffer, size_t si
 void PipeDevice::UpdateInput()
 {
   bool finished = false;
+  bool wait_for_inputs = SConfig::GetInstance().m_blockingPipes && g_needInputForFrame;
   #ifndef _WIN32
-  if(SConfig::GetInstance().m_blockingPipes && g_needInputForFrame)
+  if(wait_for_inputs)
   {
     fd_set set;
     FD_ZERO (&set);
@@ -199,7 +200,7 @@ void PipeDevice::UpdateInput()
       m_buf.erase(0, newline + 1);
       newline = m_buf.find("\n");
     }
-  } while(!finished && g_needInputForFrame && SConfig::GetInstance().m_blockingPipes);
+  } while(!finished && wait_for_inputs);
 }
 
 void PipeDevice::AddAxis(const std::string& name, double value)
@@ -264,7 +265,8 @@ bool PipeDevice::ParseCommand(const std::string& command)
 {
   if(command == "FLUSH")
   {
-    g_needInputForFrame = false;
+    // Let ControllerInterface::UpdateInputs clear the g_needInputForFrame
+    // flag after all PipeDevices have been queried.
     return true;
   }
   std::vector<std::string> tokens;