Comment 3 for bug 407519

I have a very similar problem. Since upgrading to 9.04 when trying to connect using Mobile in NetworkManger. Sometimes it will work, and other times not. I can plug in the phone and it may connect successfully. Then I disconnect and unplug, then replug and try again and the Mobile connectrion may not even show up in NetworkManager. The following appears in syslog:

Successful:

Aug 3 09:45:34 mike-laptop kernel: [29596.728079] usb 2-1: new full speed USB device using uhci_hcd and address 8
Aug 3 09:45:35 mike-laptop kernel: [29596.911410] usb 2-1: configuration #1 chosen from 1 choice
Aug 3 09:45:35 mike-laptop kernel: [29596.921401] cdc_acm 2-1:1.0: ttyACM0: USB ACM device
Aug 3 09:45:36 mike-laptop nm-system-settings: SCPlugin-Ifupdown: device added (udi: /org/freedesktop/Hal/devices/usb_device_22b8_3002_noserial_if0_serial_unknown_0_1, iface: (null)): iface not found
Aug 3 09:45:36 mike-laptop NetworkManager: <info> (ttyACM0): found serial port (udev:GSM hal:GSM)
Aug 3 09:45:36 mike-laptop NetworkManager: <info> (ttyACM0): new Modem device (driver: 'cdc_acm')
Aug 3 09:45:36 mike-laptop NetworkManager: <info> (ttyACM0): exported as /org/freedesktop/Hal/devices/usb_device_22b8_3002_noserial_if0_serial_unknown_0_1
Aug 3 09:45:39 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 1 -> 2
Aug 3 09:45:40 mike-laptop NetworkManager: <info> (ttyACM0): deactivating device (reason: 2).
Aug 3 09:45:40 mike-laptop NetworkManager: nm_system_device_flush_ip4_routes_with_iface: assertion `iface_idx >= 0' failed
Aug 3 09:45:40 mike-laptop NetworkManager: nm_system_device_flush_ip4_addresses_with_iface: assertion `iface_idx >= 0' failed
Aug 3 09:45:40 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 2 -> 3
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) starting connection 'Vodafone'
Aug 3 09:45:49 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 3 -> 4
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 1 of 5 (Device Prepare) scheduled...
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 1 of 5 (Device Prepare) started...
Aug 3 09:45:49 mike-laptop NetworkManager: <debug> [1249249549.061475] nm_serial_device_open(): (ttyACM0) opening device...
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 1 of 5 (Device Prepare) complete.
Aug 3 09:45:49 mike-laptop NetworkManager: <info> (ttyACM0): powering up...
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Registered on Home network
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Associated with network: +COPS: 0,0,"vodafone NZ"
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Connected, Woo!
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 2 of 5 (Device Configure) scheduled...
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 2 of 5 (Device Configure) starting...
Aug 3 09:45:49 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 4 -> 5
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Starting pppd connection
Aug 3 09:45:49 mike-laptop NetworkManager: <debug> [1249249549.980881] nm_ppp_manager_start(): Command line: /usr/sbin/pppd nodetach lock nodefaultroute user web ttyACM0 noipdefault noauth usepeerdns lcp-echo-failure 0 lcp-echo-interval 0 ipparam /org/freedesktop/NetworkManager/PPP/2 plugin /usr/lib/pppd/2.4.4/nm-pppd-plugin.so
Aug 3 09:45:49 mike-laptop NetworkManager: <debug> [1249249549.983901] nm_ppp_manager_start(): ppp started with pid 17024
Aug 3 09:45:49 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 2 of 5 (Device Configure) complete.
Aug 3 09:45:49 mike-laptop pppd[17024]: Plugin /usr/lib/pppd/2.4.4/nm-pppd-plugin.so loaded.
Aug 3 09:45:50 mike-laptop pppd[17024]: pppd 2.4.5 started by root, uid 0
Aug 3 09:45:50 mike-laptop pppd[17024]: Using interface ppp0
Aug 3 09:45:50 mike-laptop pppd[17024]: Connect: ppp0 <--> /dev/ttyACM0
Aug 3 09:45:50 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 5 -> 6
Aug 3 09:45:50 mike-laptop pppd[17024]: PAP authentication succeeded
Aug 3 09:45:50 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 6 -> 7
Aug 3 09:45:56 mike-laptop pppd[17024]: Cannot determine ethernet address for proxy ARP
Aug 3 09:45:56 mike-laptop pppd[17024]: local IP address 124.6.219.235
Aug 3 09:45:56 mike-laptop pppd[17024]: remote IP address 192.168.100.101
Aug 3 09:45:56 mike-laptop pppd[17024]: primary DNS address 202.73.206.16
Aug 3 09:45:56 mike-laptop pppd[17024]: secondary DNS address 202.73.198.16
Aug 3 09:45:56 mike-laptop NetworkManager: <info> PPP manager(IP Config Get) reply received.
Aug 3 09:45:56 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 4 of 5 (IP Configure Get) scheduled...
Aug 3 09:45:56 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 4 of 5 (IP Configure Get) started...
Aug 3 09:45:56 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 5 of 5 (IP Configure Commit) scheduled...
Aug 3 09:45:56 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 4 of 5 (IP Configure Get) complete.
Aug 3 09:45:56 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 5 of 5 (IP Configure Commit) started...
Aug 3 09:45:57 mike-laptop NetworkManager: <info> (ppp0): writing resolv.conf to /sbin/resolvconf
Aug 3 09:45:57 mike-laptop NetworkManager: <info> (ttyACM0): device state change: 7 -> 8
Aug 3 09:45:57 mike-laptop NetworkManager: <info> (ppp0): writing resolv.conf to /sbin/resolvconf
Aug 3 09:45:57 mike-laptop NetworkManager: <info> Policy set 'Vodafone' (ppp0) as default for routing and DNS.
Aug 3 09:45:57 mike-laptop NetworkManager: <info> Activation (ttyACM0) successful, device activated.
Aug 3 09:45:57 mike-laptop NetworkManager: <info> Activation (ttyACM0) Stage 5 of 5 (IP Configure Commit) complete.

Unsuccessful:

Aug 3 09:50:47 mike-laptop nm-system-settings: SCPlugin-Ifupdown: device added (udi: /org/freedesktop/Hal/devices/usb_device_22b8_3002_noserial_if0_serial_unknown_0_2, iface: (null)): iface not found
Aug 3 09:50:47 mike-laptop NetworkManager: <info> (ttyACM0): found serial port (udev: hal:GSM)
Aug 3 09:50:47 mike-laptop NetworkManager: <info> (ttyACM0): ignoring due to lack of probed mobile broadband capabilties

Very strange. I am using a Motorola Razor V3x. If I use GNOME PPP it works every time.