Aleksander Morgado
0e770b13f8
We have a maximum number of timeouts that could be enabled for TTY
modems, e.g. to detect whether the modem is available in the RS232
port or has been unplugged. This was required because RS232 modems
aren't notified via udev, so there was no other way to check presence
of the modem.
But, the same kind of checks may be used in order to detect failed
broken modems. If we have a modem that gets into an unstable state
where no AT port command goes through and all get timed out, we can
definitely flag the modem as invalid and get rid of it. If we don't do
this, we would end up leaving the modem exposed and available for
users of the API, but in a non-working state.
....
<info> Modem /org/freedesktop/ModemManager1/Modem/0: state changed (registered -> connecting)
<debug> Launching 3GPP connection attempt with APN 'telefonica.es'
<debug> Looking for best CID...
<debug> (ttyACM2) device open count is 2 (open)
<debug> (ttyACM2): --> 'AT+CGDCONT?<CR>'
<debug> Unexpected +CGDCONT? error: 'Serial command timed out'
<warn> (tty/ttyACM2) at port timed out 9 consecutive times
<debug> Using empty CID 1 with PDP type 'ipv4'
<debug> (ttyACM2) device open count is 3 (open)
<debug> (ttyACM2) device open count is 2 (close)
<debug> (ttyACM2): --> 'AT+CGDCONT=1,"IP","telefonica.es"<CR>'
<warn> Couldn't initialize PDP context with our APN: 'Serial command timed out'
<debug> Couldn't connect bearer '/org/freedesktop/ModemManager1/Bearer/0': 'Serial command timed out'
<info> Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connecting -> registered)
<debug> Couldn't connect bearer: 'Serial command timed out'
<debug> (ttyACM2) device open count is 1 (close)
<error> (tty/ttyACM2) at port timed out 10 consecutive times, marking modem '/org/freedesktop/ModemManager1/Modem/0' as invalid
<debug> Removing from DBus bearer at '/org/freedesktop/ModemManager1/Bearer/0'
<debug> [device /sys/devices/pci0000:00/0000:00:14.0/usb1/1-5/1-5.5] unexported modem from path '/org/freedesktop/ModemManager1/Modem/0'
<debug> Periodic signal checks disabled
<debug> (ttyACM2) device open count is 0 (close)
<debug> (ttyACM2) closing serial port...
<debug> (ttyACM2) serial port closed
<debug> (ttyACM2) forced to close port
<debug> Modem (u-blox) '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-5/1-5.5' completely disposed
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+.