monitor_reconfig: Disable LCD when using external monitor.

monitor_reconfigure_main.cc

Index: monitor_reconfigure_main.cc
diff --git a/monitor_reconfigure_main.cc b/monitor_reconfigure_main.cc
index 64c7058fdb4f9edb5b3362f808470728f57882ae..664b05f33d279248c0e66c60441724c9f70d0ea4 100644
--- a/monitor_reconfigure_main.cc
+++ b/monitor_reconfigure_main.cc
@@ -52,14 +52,20 @@ void MonitorReconfigureMain::Run() {
                                      &lcd_resolution,
                                      &external_resolution,
                                      &screen_resolution));
+  CHECK(!lcd_resolution.empty() || !external_resolution.empty());
 
-  SetDeviceResolution(lcd_output_->name, lcd_resolution);
+  // Disable the LCD if we were told to do so (because we're using a higher
+  // resolution that'd be clipped on the LCD).
+  if (!lcd_resolution.empty())
+    SetDeviceResolution(lcd_output_->name, lcd_resolution);
+  else
+    DisableDevice(lcd_output_->name);
 
   // If there's no external output connected, disable the device before we try
   // to set the screen resolution; otherwise xrandr will complain if we're
   // trying to set the screen to a smaller size than what the now-unplugged
   // device was using.
-  if (IsExternalMonitorConnected())
+  if (!external_resolution.empty())
     SetDeviceResolution(external_output_->name, external_resolution);
   else
     DisableDevice(external_output_->name);