def get_default_bios_settings(self, only_allowed_settings=True):
        """Get default BIOS settings.

        :param: only_allowed_settings: True when only allowed BIOS settings
                are to be returned. If False, All the BIOS settings supported
                by iLO are returned.
        :return: a dictionary of default BIOS settings(factory settings).
                 Depending on the 'only_allowed_settings', either only the
                 allowed settings are returned or all the supported settings
                 are returned.
        :raises: IloError, on an error from iLO.
        """
        sushy_system = self._get_sushy_system(PROLIANT_SYSTEM_ID)
        try:
            settings = sushy_system.bios_settings.default_settings
        except sushy.exceptions.SushyError as e:
            msg = (self._('The default BIOS Settings were not found. Error '
                          '%(error)s') %
                   {'error': str(e)})
            LOG.debug(msg)
            raise exception.IloError(msg)
        if only_allowed_settings:
            return common_utils.apply_bios_properties_filter(
                settings, ilo_cons.SUPPORTED_REDFISH_BIOS_PROPERTIES)
        return settings
Get default BIOS settings.

        :param: only_allowed_settings: True when only allowed BIOS settings
                are to be returned. If False, All the BIOS settings supported
                by iLO are returned.
        :return: a dictionary of default BIOS settings(factory settings).
                 Depending on the 'only_allowed_settings', either only the
                 allowed settings are returned or all the supported settings
                 are returned.
        :raises: IloError, on an error from iLO.