On Tue, 2011-11-15 at 19:33 +0100, Aleksander Morgado wrote: > > > i use a Fasttrack xTend FXT009 with an external power supply. > > > i use MM on an embedded device and the modem is connected over usb. > > > When i have an active connection with the modem, remove the power from > > > the embedded device (so MM has no chance to cleanup anything) and then i > > > restart the embedded device (and MM also restarts), MM can not handle > > > the modem because the modem is still in connection mode. > > > i talked to aleksander on irc and a simple solution is to send "+++" > > > before any other at-command. > > > any problems expected with this solution? > > > > It depends on the modem. '+++' is one of the ways to break out of > > "data" mode and into "AT" mode, but it's only one of a few. Others > > include dropping DTR for a while or "flashing" the port, and some of > > this depends on the settings you send in the initialization string. One > > question I've got though is if you're removing power from the modem, > > does NM get a port removed signal from udev? That's the expected > > sequence here. If you remove the device, the kernel should notice that, > > send a remove event to MM (through udev) and MM should clean up the > > device anyway. Is that not happening? > > > > The case here is the opposite. ModemManager (or the whole PC) gets > rebooted; while the modem itself is always powered on (and connected). > Therefore, this issue is only applicable to modems with an external > power supply, like the Fastrack and Cinterion/Siemens ones (at least). > If sending '+++' works for this case, we could extend those plugins with > a new custom init command just doing that. > > Although it seems to me that the modems should be able to detect that > the link with the DTE is down, and drop the connection automatically in > that case.
Yeah, though implementation is dicey. AT&Dx is one way to do this but of course then we have to twiddle serial port bits and stuff too. Closing the port should also cause a hangup and force the modem to drop the data stream, but not all do that for various reasons. Adding +++ to probing isn't a bad idea, and will be even better when we are just probing for AT compatibility instead of the whole 6-level probing scheme. Dan _______________________________________________ networkmanager-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/networkmanager-list
