diff -r 91694d19d7b2 content/canvas/src/nsGLPbufferGLX.cpp
--- a/content/canvas/src/nsGLPbufferGLX.cpp	Fri Apr 09 15:55:11 2010 -0700
+++ b/content/canvas/src/nsGLPbufferGLX.cpp	Mon Apr 12 14:32:30 2010 -0400
@@ -195,7 +195,7 @@
                      GLX_SAMPLES, 1 << prefAntialiasing,
                      None };
     if (prefAntialiasing <= 0)
-      attrib[16] = 0;
+      attrib[14] = None;
     int num;
     GLXFBConfig *configs = gGLXWrap.fChooseFBConfig(mDisplay, DefaultScreen(mDisplay),
                                                     attrib, &num);