diff -ur glxinfo.orig/glxinfo.c glxinfo/glxinfo.c
--- glxinfo.orig/glxinfo.c	2004-07-29 21:18:52.000000000 +0200
+++ glxinfo/glxinfo.c	2009-01-20 18:10:08.000000000 +0100
@@ -35,6 +35,8 @@
  * Brian Paul  26 January 2000
  */
 
+#define _GNU_SOURCE
+
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <GL/gl.h>
@@ -323,6 +325,11 @@
       fprintf(stderr, "Error: glXMakeCurrent failed\n");
    }
 
+   if (! glXIsDirect(dpy, ctx))
+       printf ("\n***\n*** WARNING: Direct Rendering is NOT enabled\n***\n\n");
+   else if (strcasestr ((char *) glGetString(GL_RENDERER), "software"))
+       printf ("\n***\n*** WARNING: Hardware acceleration is NOT active\n***\n\n");
+
    glXDestroyContext(dpy, ctx);
    XDestroyWindow(dpy, win);
 }