diff --git a/src/util/00-mesa-defaults.conf b/src/util/00-mesa-defaults.conf
index fc4dd2fcd42..d53f9be4518 100644
--- a/src/util/00-mesa-defaults.conf
+++ b/src/util/00-mesa-defaults.conf
@@ -636,6 +636,12 @@ TODO: document the other workarounds.
         </application>
     </device>
     <device driver="radeonsi">
+        <application name="Half Life 2" executable="hl2_linux">
+            <option name="mesa_glthread" value="true" />
+        </application>
+        <application name="Black Mesa" executable="bms_linux">
+            <option name="mesa_glthread" value="true" />
+        </application>
         <application name="Alien Isolation" executable="AlienIsolation">
             <option name="force_gl_vendor" value="X.Org" />
         </application>