Comment 3 for bug 683996

Ok, so this isn't sufficient - its probably necessary, but there seems to be a race or other bug making probing still happen - and when it probes its a 50/50 chance whether USB1 or USB3 is detected and wins.

A bad insertion looks like this:
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB0) opening serial device...
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB0): probe requested by plugin 'ZTE'
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB1) opening serial device...
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB1): probe requested by plugin 'ZTE'
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB2) opening serial device...
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB2): probe requested by plugin 'ZTE'
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB3) opening serial device...
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB3): probe requested by plugin 'ZTE'
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB4) opening serial device...
Dec 2 20:26:32 lifeless-64 modem-manager: (ttyUSB4): probe requested by plugin 'ZTE'
Dec 2 20:26:38 lifeless-64 modem-manager: Got failure code 100: Unknown error
Dec 2 20:26:38 lifeless-64 modem-manager: Got failure code 100: Unknown error
Dec 2 20:26:38 lifeless-64 modem-manager: Got failure code 14: SIM busy
Dec 2 20:26:47 lifeless-64 modem-manager: (ttyUSB1) closing serial device...
Dec 2 20:26:47 lifeless-64 modem-manager: (ttyUSB2) closing serial device...
Dec 2 20:26:47 lifeless-64 modem-manager: (ttyUSB3) closing serial device...
Dec 2 20:26:47 lifeless-64 modem-manager: (ttyUSB1) opening serial device...
Dec 2 20:26:47 lifeless-64 modem-manager: (ZTE): GSM modem /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 claimed port ttyUSB1
Dec 2 20:26:47 lifeless-64 modem-manager: Added modem /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:26:47 lifeless-64 modem-manager: (tty/ttyUSB0): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:26:47 lifeless-64 modem-manager: (tty/ttyUSB0): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:26:47 lifeless-64 modem-manager: mm_modem_base_add_port: assertion `port == NULL' failed
Dec 2 20:26:47 lifeless-64 modem-manager: (mm-generic-gsm.c:530):mm_generic_gsm_grab_port: runtime check failed: (port != NULL)
Dec 2 20:26:47 lifeless-64 modem-manager: do_grab_port: plugin 'ZTE' claimed to support tty/ttyUSB2 but couldn't: (-1) (unknown)
Dec 2 20:26:47 lifeless-64 modem-manager: (tty/ttyUSB0): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:26:47 lifeless-64 modem-manager: (ZTE): GSM modem /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 claimed port ttyUSB3
Dec 2 20:26:47 lifeless-64 modem-manager: (tty/ttyUSB0): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:26:47 lifeless-64 modem-manager: (tty/ttyUSB0): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:26:47 lifeless-64 modem-manager: (ttyUSB1) closing serial device...
Dec 2 20:27:07 lifeless-64 modem-manager: (ttyUSB0) closing serial device...
Dec 2 20:27:07 lifeless-64 modem-manager: (ttyUSB0) opening serial device...
Dec 2 20:27:09 lifeless-64 modem-manager: (ttyUSB4) closing serial device...
Dec 2 20:27:09 lifeless-64 modem-manager: (ttyUSB4) opening serial device...
Dec 2 20:27:10 lifeless-64 modem-manager: (ttyUSB0) closing serial device...
Dec 2 20:27:10 lifeless-64 modem-manager: (ZTE): GSM modem /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 claimed port ttyUSB0
Dec 2 20:27:10 lifeless-64 modem-manager: (tty/ttyUSB4): outstanding support task prevents export of /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2
Dec 2 20:27:15 lifeless-64 modem-manager: (ttyUSB4) closing serial device...
Dec 2 20:27:15 lifeless-64 modem-manager: (tty/ttyUSB4): ignoring port unsupported by physical modem's plugin
Dec 2 20:27:15 lifeless-64 modem-manager: Exported modem /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 as /org/freedesktop/ModemManager/Modems/3
Dec 2 20:27:15 lifeless-64 modem-manager: (/org/freedesktop/ModemManager/Modems/3): data port is ttyUSB1
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <warn> (ttyUSB1): failed to look up interface index
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): new GSM device (driver: 'option1' ifindex: -1)
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): exported as /org/freedesktop/NetworkManager/Devices/5
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): now managed
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): device state change: 1 -> 2 (reason 2)
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): deactivating device (reason: 2).
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): device state change: 2 -> 3 (reason 0)
Dec 2 20:27:15 lifeless-64 NetworkManager[1137]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Dec 2 20:27:35 lifeless-64 NetworkManager[1137]: <info> Activation (ttyUSB1) starting connection 'Vodafone Prepaid'
Dec 2 20:27:35 lifeless-64 NetworkManager[1137]: <info> (ttyUSB1): device state change: 3 -> 4 (reason 0)
Dec 2 20:27:35 lifeless-64 NetworkManager[1137]: <info> Unmanaged Device found; state CONNECTED forced. (see http://bugs.launchpad.net/bugs/191889)
Dec 2 20:27:35 lifeless-64 NetworkManager[1137]: <info> Activation (ttyUSB1) Stage 1 of 5 (Device Prepare) scheduled...
Dec 2 20:27:35 lifeless-64 NetworkManager[1137]: <info> Activation (ttyUSB1) Stage 1 of 5 (Device Prepare) started...
Dec 2 20:27:35 lifeless-64 NetworkManager[1137]: <info> Activation (ttyUSB1) Stage 1 of 5 (Device Prepare) complete.
Dec 2 20:27:35 lifeless-64 modem-manager: (ttyUSB1) opening serial device...
Dec 2 20:27:35 lifeless-64 modem-manager: Modem /org/freedesktop/ModemManager/Modems/3: state changed (disabled -> enabling)
Dec 2 20:27:35 lifeless-64 modem-manager: (ttyUSB3) opening serial device...
Dec 2 20:27:36 lifeless-64 modem-manager: Modem /org/freedesktop/ModemManager/Modems/3: state changed (enabling -> enabled)
Dec 2 20:27:36 lifeless-64 modem-manager: CS registration state changed: 1
Dec 2 20:27:36 lifeless-64 modem-manager: Modem /org/freedesktop/ModemManager/Modems/3: state changed (enabled -> registered)
Dec 2 20:27:36 lifeless-64 modem-manager: Got failure code 100: Unknown error
Dec 2 20:27:36 lifeless-64 modem-manager: PS registration state changed: 1
Dec 2 20:27:36 lifeless-64 modem-manager: Modem /org/freedesktop/ModemManager/Modems/3: state changed (registered -> connecting)
Dec 2 20:27:36 lifeless-64 modem-manager: Got failure code 3: No carrier
Dec 2 20:27:36 lifeless-64 modem-manager: Modem /org/freedesktop/ModemManager/Modems/3: state changed (connecting -> registered)
Dec 2 20:27:36 lifeless-64 NetworkManager[1137]: <warn> GSM connection failed: (32) No cause information available