Yesterday I wrote a somewhat longer post on how to use the Archos 3G USB stick with an Archos G9 and Plasma Active. What I forgot to mention is that, even though it generally works, there are still some, for now, possibly random issues.

The cause of the problem is that the Archos 3G stick has two device nodes (/dev/ttyUSB3 and /dev/ttyUSB4) that are detected as WWAN interfaces. That a WWAN or UMTS stick is detected as two devices showing up as WWAN interfaces does, usually, not seem to be an issue. Ususally, it seems that one is treated as primary and the other as secondary device.

However, there is the problem that modem-manager sometimes swaps the order in which the primary and secondary device are assigned. The correct order for UMTS to work correctly is that /dev/ttyUSB4 is the primary and /dev/ttyUSB3 the secondary device.

This can be easily checked with the modem-manager debug output:

...
modem-manager[3794]:  [1349557760.261848] [mm-modem-base.c:155] mm_modem_base_add_port(): (ttyUSB4) type primary claimed by /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-7
...
modem-manager[3794]:  [1349557760.266845] [mm-modem-base.c:155] mm_modem_base_add_port(): (ttyUSB3) type secondary claimed by /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-7
...

In the above listing the correct order is shown. Once the 3G stick had been detected it might take up to, say, 20 seconds until it is recognized by NetworkManager. Once it is recognized the debug output of NetworkManager looks like something as follows:

NetworkManager[3627]:  (ttyUSB4): failed to look up interface index
NetworkManager[3627]:  (ttyUSB4): new GSM/UMTS device (driver: 'generic' ifindex: 0)
NetworkManager[3627]:  (ttyUSB4): exported as /org/freedesktop/NetworkManager/Devices/2
NetworkManager[3627]:  (ttyUSB4): now managed
NetworkManager[3627]:  (ttyUSB4): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
NetworkManager[3627]:  (ttyUSB4): deactivating device (reason 'managed') [2]

If the order of ttyUSB3 and ttyUSB4 is swapped then here ttyUSB3 would appear. In this case the device will still show up in the network management applet but the connection setup will fail. If this happens the output of NetworkManager will be something like shown in the following listing:

...
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 3 of 5 (IP Configure Start) started...
NetworkManager[3260]: <info> (ttyUSB3): device state change: config -> ip-config (reason 'none') [50 70 0]
NetworkManager[3260]: <info> starting PPP connection
NetworkManager[3260]: <info> pppd started with pid 3945
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 4 of 5 (IPv6 Configure Timeout) scheduled...
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 3 of 5 (IP Configure Start) complete.
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 4 of 5 (IPv6 Configure Timeout) started...
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 4 of 5 (IPv6 Configure Timeout) complete.
Plugin /usr/lib64/pppd/2.4.5/nm-pppd-plugin.so loaded.
** Message: nm-ppp-plugin: (plugin_init): initializing
** Message: nm-ppp-plugin: (nm_phasechange): status 3 / phase 'serial connection'
Removed stale lock on ttyUSB3 (pid 3818)
using channel 7
Using interface ppp0
Connect: ppp0 <--> /dev/ttyUSB3
** Message: nm-ppp-plugin: (nm_phasechange): status 5 / phase 'establish'
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
NetworkManager[3260]: <warn> /sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6c227513> <pcomp> <accomp>]
NetworkManager[3260]: <warn> pppd timed out or didn't initialize our dbus module
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 4 of 5 (IPv4 Configure Timeout) scheduled...
Terminating on signal 15
NetworkManager[3260]: <info> Activation (ttyUSB3) Stage 4 of 5 (IPv4 Configure Timeout) started...
NetworkManager[3260]: <info> (ttyUSB3): device state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]** Message: nm-ppp-plugin: (nm_phasechange): status 10 / phase 'terminate'
...

Note the repetition of the lines starting with "sent" shown here. It seems like that in the case of ttyUSB3 being the primary device pppd somehow does not get a response from the provider side.

For now, I couldn’t identify the reason why the two ttyUSB devices are swapped or not. However, all this shows, that, generally, WWAN is possible on Archos G9 with Plasma Active.

The problem sketched above only occurred pretty seldom during my tests here. It usually occurred sometimes when I woke my tablet up from sleep. In this case suspending the tablet and waking it up again was sufficient to solve this issue.