Xorg+dummy: set resolution to first size in list

remoting/host/linux/linux_me2me_host.py

 #!/usr/bin/python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Virtual Me2Me implementation.  This script runs and manages the processes
 # required for a Virtual Me2Me desktop, which are: X server, X desktop
 # session, and Host process.
 # This script is intended to run continuously as a background daemon
 # process, running under an ordinary (non-root) user account.
@@ skipping 326 matching lines @@
 
   def __init__(self, sizes):
     self.x_proc = None
     self.session_proc = None
     self.host_proc = None
     self.child_env = None
     self.sizes = sizes
     self.xorg_conf = None
     self.pulseaudio_pipe = None
     self.server_supports_exact_resize = False
+    self.server_supports_randr = False
+    self.randr_add_sizes = False
     self.host_ready = False
     self.ssh_auth_sockname = None
     g_desktops.append(self)
 
   @staticmethod
   def get_unused_display_number():
     """Return a candidate display number for which there is currently no
     X Server lock file"""
     display = FIRST_X_DISPLAY_NUMBER
     while os.path.exists(X_LOCK_FILE_TEMPLATE % display):
@@ skipping 103 matching lines @@
     self.ssh_auth_sockname = ("/tmp/chromoting.%s.ssh_auth_sock" %
                               os.environ["USER"])
 
   def _launch_xvfb(self, display, x_auth_file, extra_x_args):
     max_width = max([width for width, height in self.sizes])
     max_height = max([height for width, height in self.sizes])
 
     xvfb = locate_xvfb_randr()
     if xvfb:
       self.server_supports_exact_resize = True
+      self.server_supports_randr = True
+      self.randr_add_sizes = True
     else:
       xvfb = "Xvfb"
       self.server_supports_exact_resize = False
+      self.server_supports_randr = False
 
     logging.info("Starting %s on display :%d" % (xvfb, display))
     screen_option = "%dx%dx24" % (max_width, max_height)
     self.x_proc = subprocess.Popen(
         [xvfb, ":%d" % display,
          "-auth", x_auth_file,
          "-nolisten", "tcp",
          "-noreset",
          "-screen", "0", screen_option
         ] + extra_x_args)
     if not self.x_proc.pid:
       raise Exception("Could not start Xvfb.")
 
   def _launch_xorg(self, display, x_auth_file, extra_x_args):
     with tempfile.NamedTemporaryFile(
         prefix="chrome_remote_desktop_",
         suffix=".conf", delete=False) as config_file:
       config_file.write(gen_xorg_config(self.sizes))
 
-    # For now, we don't support exact resize with Xorg+dummy
+    # We can't support exact resize with the current Xorg dummy driver.
     self.server_supports_exact_resize = False
+    # But dummy does support RandR 1.0.
+    self.server_supports_randr = True
     self.xorg_conf = config_file.name
 
     logging.info("Starting Xorg on display :%d" % display)
     # We use the child environment so the Xorg server picks up the Mesa libGL
     # instead of any proprietary versions that may be installed, thanks to
     # LD_LIBRARY_PATH.
     # Note: This prevents any environment variable the user has set from
     # affecting the Xorg server.
     self.x_proc = subprocess.Popen(
         ["Xorg", ":%d" % display,
@@ skipping 63 matching lines @@
     # starts configured to use the "base" ruleset, resulting in XKB configuring
     # for "xfree86" keycodes, and screwing up some keys. See crbug.com/119013.
     # Reconfigure the X server to use "evdev" keymap rules.  The X server must
     # be started with -noreset otherwise it'll reset as soon as the command
     # completes, since there are no other X clients running yet.
     retcode = subprocess.call("setxkbmap -rules evdev", env=self.child_env,
                               shell=True)
     if retcode != 0:
       logging.error("Failed to set XKB to 'evdev'")
 
-    if not self.server_supports_exact_resize:
+    if not self.server_supports_randr:
       return
 
-    # Register the screen sizes if the X server's RANDR extension supports it.
-    # Errors here are non-fatal; the X server will continue to run with the
-    # dimensions from the "-screen" option.
-    for width, height in self.sizes:
-      label = "%dx%d" % (width, height)
-      args = ["xrandr", "--newmode", label, "0", str(width), "0", "0", "0",
-              str(height), "0", "0", "0"]
-      subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)
-      args = ["xrandr", "--addmode", "screen", label]
-      subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)
+    # Register the screen sizes with RandR, if needed.  Errors here are
+    # non-fatal; the X server will continue to run with the dimensions from the
+    # "-screen" option.
+    if self.randr_add_sizes:
+      for width, height in self.sizes:
+        label = "%dx%d" % (width, height)
+        args = ["xrandr", "--newmode", label, "0", str(width), "0", "0", "0",
+                str(height), "0", "0", "0"]
+        subprocess.call(args, env=self.child_env, stdout=devnull,
+                        stderr=devnull)
+        args = ["xrandr", "--addmode", "screen", label]
+        subprocess.call(args, env=self.child_env, stdout=devnull,
+                        stderr=devnull)
 
     # Set the initial mode to the first size specified, otherwise the X server
     # would default to (max_width, max_height), which might not even be in the
     # list.
     initial_size = self.sizes[0]
     label = "%dx%d" % initial_size
     args = ["xrandr", "-s", label]
     subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)
 
     # Set the physical size of the display so that the initial mode is running
@@ skipping 918 matching lines @@
         else:
           logging.info("Host exited with status %s." % os.WEXITSTATUS(status))
       elif os.WIFSIGNALED(status):
         logging.info("Host terminated by signal %s." % os.WTERMSIG(status))
 
 
 if __name__ == "__main__":
   logging.basicConfig(level=logging.DEBUG,
                       format="%(asctime)s:%(levelname)s:%(message)s")
   sys.exit(main())