diff --git a/src/glx/glxcmds.c b/src/glx/glxcmds.c
index cf546cc86dd..fcd82bab4a4 100644
--- a/src/glx/glxcmds.c
+++ b/src/glx/glxcmds.c
@@ -276,7 +276,8 @@ glx_context_init(struct glx_context *gc,
  *
  * \param dpy        Display where the context was created.
  * \param contextID  ID of the context to be tested.
- * \param error      Out parameter, set to True on error if not NULL
+ * \param error      Out parameter, set to True on error if not NULL,
+ *                   otherwise raise the error to the application.
  *
  * \returns \c True if the context is direct rendering or not.
  */
@@ -301,7 +302,8 @@ __glXIsDirect(Display * dpy, GLXContextID contextID, Bool *error)
    if (err != NULL) {
       if (error)
          *error = True;
-      __glXSendErrorForXcb(dpy, err);
+      else
+         __glXSendErrorForXcb(dpy, err);
       free(err);
    }