[chaley]

I have a version of the 'connected_device_name' built-in template function that returns the configured device name. I also found the problem causing the incorrect value (a value) displayed in the selected book when the device disconnects. There is a race condition in gui2.device.

FYI: here is the source of the function.

    def evaluate(self, formatter, kwargs, mi, locals, storage_location):
        if hasattr(mi, '_proxy_metadata'):
            # Do the import here so that we don't entangle the GUI when using
            # command line functions
            from calibre.gui2.ui import get_gui
            info = get_gui().device_manager.get_current_device_information()
            if info is None:
                return ''
            try:
                if storage_location not in {'main', 'carda', 'cardb'}:
                    raise ValueError(
                         _('connected_device_name: invalid storage location "{0}"'
                                    .format(storage_location)))
                info = info['info'][4]
                if storage_location not in info:
                    return ''
                return info[storage_location]['device_name']
            except:
                traceback.print_exc()
                raise
        return _('This function can be used only in the GUI')