Dan Williams
d63dcd682d
Some devices (8775 specifically) get angry if you don't check for a PS attach before dialing. The next time they try to connect, they'll continuously report "searching" as the registration status and return CME ERROR 30 (No Network Service) for lots of requests. So initiate a PS attach (which should return OK if the modem is already attached) before dialing, and if that fails cancel the dial attempt. See http://mail.gnome.org/archives/networkmanager-list/2010-October/msg00072.html "I talked about this problem with a contact at SierraWireless. He said that a firmware upgrade will not help in this case. But what can help is checking for PS attach and dial only if PS attach status is attached. Dialing without PS attach can bring modem into unwanted condition that sometimes restart is needed to recover."
ModemManager. The problem ModemManager tries to solve is to provide a unified high level API for communicating with (mobile broadband) modems. While the basic commands are standardized, the more advanced operations (like signal quality monitoring while connected) varies a lot. Using. ModemManager is a system daemon and is not meant to be used directly from the command line. However, since it provides DBus API, it is possible to use 'dbus-send' command to control it from the terminal. There's an example program (tests/mm-test.py) that demonstrates the basic API usage. Implementation. ModemManager is a DBus system bus activated service (meaning it's started automatically when a request arrives). It is written in C. The devices are queried from HAL and automatically updated based on hardware events. There's a GInterface (MMModem) that defines the modem interface and any device specific implementation must implement it. There are two generic MMModem implementations to support the basic operations (one for GSM, one for CDMA,) which are common for all cards. Plugins. Plugins are loaded on startup, and must implement the MMPlugin interface. It consists of a couple of methods which tell the daemon whether the plugin supports a HAL UDI and to create custom MMModem implementations. It most likely makes sense to derive custom modem implementations from one of the generic classes and just add (or override) operations which are not standard. There's a fully working plugin in the plugins/ directory for Huawei cards that can be used as an example for writing new plugins. Writing new plugins is highly encouraged! API. The API is open for changes, so if you're writing a plugin and need to add or change some public method, feel free to suggest it!