diff --git a/docs/envvars.html b/docs/envvars.html
index 9e2f8163644..ca553e5397f 100644
--- a/docs/envvars.html
+++ b/docs/envvars.html
@@ -46,7 +46,7 @@ sometimes be useful for debugging end-user issues.
 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
-<li>MESA_NO_ERROR - if set error checking is disabled as per KHR_no_error.
+<li>MESA_NO_ERROR - if set to 1, error checking is disabled as per KHR_no_error.
    This will result in undefined behaviour for invalid use of the api, but
    can reduce CPU use for apps that are known to be error free.</li>
 <li>MESA_DEBUG - if set, error messages are printed to stderr.  For example,