Index: gnome-shell-2.91.6/src/gnome-shell.in
===================================================================
--- gnome-shell-2.91.6.orig/src/gnome-shell.in
+++ gnome-shell-2.91.6/src/gnome-shell.in
@@ -192,7 +192,9 @@ def _get_glx_extensions():
 
     glxinfo = subprocess.Popen(["glxinfo"], stdout=subprocess.PIPE)
     glxinfo_output = glxinfo.communicate()[0]
-    glxinfo.wait()
+    ret = glxinfo.wait()
+    if ret != 0:
+        return (set(), set(), set())
 
     glxinfo_map = {}
     for m in GLXINFO_RE.finditer(glxinfo_output):