reported upstream as https://www.xpra.org/trac/ticket/367#ticket
upstream adapted the print_bool part in https://www.xpra.org/trac/changeset/3761/xpra

--- xpra-0.9.5/xpra/scripts/config.py
+++ xpra-0.9.5/xpra/scripts/config.py
@@ -117,9 +117,10 @@
         if e.args[0]==errno.EACCES:
             return "VirtualBox is present (VBoxMiniRdrDN)"
     return None
-OPENGL_DEFAULT = False
-#if OpenGL_safety_check() is not None:
-#    OPENGL_DEFAULT = False
+if OpenGL_safety_check() is not None:
+    OPENGL_DEFAULT = False
+else:
+    OPENGL_DEFAULT = None
 
 
 
@@ -452,6 +453,13 @@
     else:
         warn("Warning: cannot parse value '%s' for '%s' as a boolean" % (v, k))
 
+def print_bool(k, v):
+    if type(v)==type(None):
+	return 'auto'
+    if type(v)==bool:
+	return v and 'yes' or 'no'
+    warn("Warning: cannot print value '%s' for '%s' as a boolean" % (v, k))
+
 def parse_number(numtype, k, v, auto=-1):
     if type(v)==str:
         v = v.lower()
--- xpra-0.9.5/xpra/scripts/main.py
+++ xpra-0.9.5/xpra/scripts/main.py
@@ -24,7 +24,7 @@
                            get_default_socket_dir,
                            init as platform_init)
 from xpra.bytestreams import TwoFileConnection, SocketConnection
-from xpra.scripts.config import ENCODINGS, ENCRYPTION_CIPHERS, make_defaults_struct, show_codec_help, parse_bool
+from xpra.scripts.config import ENCODINGS, ENCRYPTION_CIPHERS, make_defaults_struct, show_codec_help, parse_bool, print_bool
 from wimpiggy.gobject_compat import import_gobject
 
 SIGNAMES = {signal.SIGINT:"SIGINT", signal.SIGTERM:"SIGTERM"}
@@ -253,7 +253,7 @@
                 "These options control client features that affect the appearance or the keyboard.")
     parser.add_option_group(group)
     group.add_option("--opengl", action="store",
-                      dest="opengl", default=defaults.opengl,
+                      dest="opengl", default=print_bool('opengl', defaults.opengl),
                       help="Use OpenGL accelerated rendering, options: yes,no,auto. Default: %default.")
     group.add_option("--no-windows", action="store_false",
                       dest="windows", default=defaults.windows,