monitor_reconfig: Disable external output to avoid error.

monitor_reconfigure_main.cc

Index: monitor_reconfigure_main.cc
diff --git a/monitor_reconfigure_main.cc b/monitor_reconfigure_main.cc
index b73e7eaa3ada95cef569f0a38d4c4f6b4dabe2fd..64c7058fdb4f9edb5b3362f808470728f57882ae 100644
--- a/monitor_reconfigure_main.cc
+++ b/monitor_reconfigure_main.cc
@@ -54,8 +54,16 @@ void MonitorReconfigureMain::Run() {
                                      &screen_resolution));
 
   SetDeviceResolution(lcd_output_->name, lcd_resolution);
+
+  // 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())
     SetDeviceResolution(external_output_->name, external_resolution);
+  else
+    DisableDevice(external_output_->name);
+
   SetScreenResolution(screen_resolution);
 }
 
@@ -122,6 +130,13 @@ bool MonitorReconfigureMain::SetScreenResolution(
   return system(command.c_str()) == 0;
 }
 
+bool MonitorReconfigureMain::DisableDevice(const std::string& device_name) {
+  string command = StringPrintf("xrandr --output %s --off",
+                                device_name.c_str());
+  LOG(INFO) << "Running " << command.c_str();
+  return system(command.c_str()) == 0;
+}
+
 }  // end namespace monitor_reconfig
 
 int main(int argc, char** argv) {