When i unplug the modem device, modem-manager hava some error message

[bensonwu <bensonwu linpus com>]

Hi
	when i unplug the modem device, the modem-manager often have some fail
messages, as follow:

 ** (modem-manager:3859): CRITICAL **: mm_serial_port_flash: assertion
`MM_IS_SERIAL_PORT (self)' failed

(modem-manager:3859): GLib-GObject-CRITICAL **:
g_type_instance_get_private: assertion `instance != NULL &&
instance->g_class != NULL' failed

** (modem-manager:3859): CRITICAL **: internal_queue_command: assertion
`MM_IS_SERIAL_PORT (self)' failed

	when i re-insert the modem device, the modem-manager have no response.
	if no fail messages when pull-out the device, the modem-manager is
normal when re-insert the modem device.
	can you tell me why? thanks.
						benson