Aleksander Morgado
dbc64d83ba
Modems which only expose a single port will not be able to update the signal quality value while in connected mode. The signal quality value reported in this case, while the modem is connected, will be the last signal quality value read before the connection. The additional boolean value proposed here in the SignalQuality property will just say if the given signal quality was recently taken (if TRUE) or cached some time ago (if FALSE). The time to assume the value was recently taken or not could depend on different things, for example: * If the modem always has an AT port, even if connected, we could directly query the current signal quality and report the value as being fresh. * If the modem has a single port, we could report the value as not being fresh as soon as the modem gets in connected state. * For modems which report the signal quality updates in unsolicited messages, we could report the value as being fresh if the update was received in the last minute or so.
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 udev 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 port 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!