diff --git a/README.md b/README.md
index 2295eb54..d68fafb8 100644
--- a/README.md
+++ b/README.md
@@ -153,5 +153,6 @@ the Wine prefix. Removing the option will revert to the previous behavior.
 | :-------------------- | :----------------------------- | :----------- |
 | <tt>wined3d11</tt>    | <tt>PROTON_USE_WINED3D11</tt>  | Use OpenGL-based wined3d instead of Vulkan-based DXVK for d3d11. |
 | <tt>nod3d11</tt>      | <tt>PROTON_NO_D3D11</tt>       | Disable <tt>d3d11.dll</tt>, for games which can fall back to and run better with d3d9. |
+| <tt>noesync</tt>      | <tt>PROTON_NO_ESYNC</tt>       | Do not use eventfd-based in-process synchronization primitives. |
 
 <!-- Target:  GitHub Flavor Markdown.  To test locally:  pandoc -f markdown_github -t html README.md  -->
diff --git a/proton b/proton
index 04ab666c..4ac49151 100755
--- a/proton
+++ b/proton
@@ -65,6 +65,7 @@ else:
 
 check_environment("PROTON_USE_WINED3D11", "wined3d11")
 check_environment("PROTON_NO_D3D11", "nod3d11")
+check_environment("PROTON_NO_ESYNC", "noesync")
 
 basedir = os.path.dirname(sys.argv[0])
 bindir = basedir + "/dist/bin/"
@@ -110,6 +111,9 @@ else:
 
 env["WINEDLLPATH"] = lib64dir + "/wine:" + libdir + "/wine"
 
+if not "noesync" in config_opts:
+    env["WINEESYNC"] = "1"
+
 if "PATH" in os.environ:
     env["PATH"] = bindir + ":" + os.environ["PATH"]
 else: