Ben Chan
5e5160c46a
ModemManager currently relies on unsolicited MBIM_CID_SIGNAL_STATE notifications to obtain signal quality updates, and it doesn't query the initial signal quality. It's been observed that some MBIM modems issue a MBIM_CID_SIGNAL_STATE notification only when there is a notable change in RSSI. The signal quality may remain at 0 for quite some time. It's more noticeable when simply restarting ModemManager after the modem has been initialized and enabled once. We could simply enable periodic signal check on an MBIM modem, but that's less ideal as it may unnecessarily wake the modem up from USB selective suspend (unless we use a much longer polling period). To address the issue, this patch adds the implementation of load_signal_quality to MMBroadbandModemMbim so that the signal quality is initially polled via a solicited MBIM_CID_SIGNAL_STATE query. To avoid the periodic signal check, we set the MM_IFACE_MODEM_PERIODIC_SIGNAL_CHECK_DISABLED property to TRUE for MMBroadbandModemMbim.
ModemManager. ModemManager provides a unified high level API for communicating with mobile broadband modems, regardless of the protocol used to communicate with the actual device (Generic AT, vendor-specific AT, QCDM, QMI, MBIM...). Using. ModemManager is a system daemon and is not meant to be used directly from the command line. However, since it provides a DBus API, it is possible to use 'dbus-send' commands or the new 'mmcli' command line interface to control it from the terminal. The devices are queried from udev and automatically updated based on hardware events, although a manual re-scan can also be requested to look for RS232 modems. Implementation. ModemManager is a DBus system bus activated service (meaning it's started automatically when a request arrives). It is written in C, using glib and gio. Several GInterfaces specify different features that the modems support, including the generic MMIfaceModem3gpp and MMIfaceModemCdma which provice basic operations for 3GPP (GSM, UMTS, LTE) or CDMA (CDMA1x, EV-DO) modems. If a given feature is not available in the modem, the specific interface will not be exported in DBus. 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 MMBroadbandModem 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 are multiple fully working plugins in the plugins/ directory that can be used as an example for writing new plugins. Writing new plugins is highly encouraged! The plugin 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! License. The ModemManager and mmcli binaries are both GPLv2+. The libmm-glib library is LGPLv2+.