From 3926db624d5ab2f959e67eb2369f1fe5f0f9543a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9o=20Lam?= <leo@innovatetechnologi.es>
Date: Fri, 15 Jul 2016 11:34:18 +0200
Subject: [PATCH] ControllerInterface: Don't block on UpdateInput()

Changes UpdateInput() to skip if we can't lock the mutex, instead of
potentially blocking the CPU thread and causing a short but noticeable
frame drop.
---
 .../ControllerInterface/ControllerInterface.cpp        | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
index cf726698f1..9c7a08428e 100644
--- a/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/ControllerInterface.cpp
@@ -175,9 +175,13 @@ void ControllerInterface::RemoveDevice(std::function<bool(const ciface::Core::De
 //
 void ControllerInterface::UpdateInput()
 {
-  std::lock_guard<std::mutex> lk(m_devices_mutex);
-  for (const auto& d : m_devices)
-    d->UpdateInput();
+  // Don't block the UI or CPU thread (to avoid a short but noticeable frame drop)
+  if (m_devices_mutex.try_lock())
+  {
+    std::lock_guard<std::mutex> lk(m_devices_mutex, std::adopt_lock);
+    for (const auto& d : m_devices)
+      d->UpdateInput();
+  }
 }
 
 //