diff --git a/src/util/00-mesa-defaults.conf b/src/util/00-mesa-defaults.conf
index ba343ec5ffb..734161650b7 100644
--- a/src/util/00-mesa-defaults.conf
+++ b/src/util/00-mesa-defaults.conf
@@ -243,6 +243,13 @@ TODO: document the other workarounds.
             <option name="force_compat_profile" value="true" />
         </application>
 
+        <application name="GpuTest" executable="GpuTest">
+            <!-- GiMark benchmark from GpuTest does not initialize .w channel of
+                 lightDir0 and lightDir1 varyings in the vertex shader while
+                 uses it in the fragment shader. -->
+            <option name="glsl_zero_init" value="true"/>
+        </application>
+
         <!-- The GL thread whitelist is below, workarounds are above.
              Keep it that way. -->