libqofono Can't get modems for because of error_name=org.freedesktop.DBus.Error.MatchRuleNotFound
Unsolved
Mobile and Embedded
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I am trying to use libqofono-0.92 (a Qt library developed by Sailfish OS and ported to Ubuntu and Yocto) in an embedded machine in order to retrieve modems from ofono's DBus API. I am looking for people who used it before or encountered the error I'm having. Here's what I have in code from test examples:
QOfonoManager manager; QOfonoModem modem; QStringList modems = manager.modems();The output of
modemsis null. WhenQOfonoManageris instantiated, the dbus monitoring output is as follows:method call time=1537964753.056662 sender=:1.86 -> destination=org.freedesktop.DBus serial=7 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch string "type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0='org.ofono'" method call time=1537964753.056723 sender=:1.86 -> destination=org.freedesktop.DBus serial=8 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetNameOwner string "org.ofono" method return time=1537964753.056776 sender=org.freedesktop.DBus -> destination=:1.86 serial=5 reply_serial=8 string ":1.62" method call time=1537964753.056818 sender=:1.86 -> destination=org.freedesktop.DBus serial=9 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=AddMatch string "type='signal',sender='org.ofono',path='/',interface='org.ofono.Manager',member='ModemRemoved'" method call time=1537964753.056868 sender=:1.86 -> destination=org.freedesktop.DBus serial=10 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameHasOwner string "org.ofono" method return time=1537964753.056924 sender=org.freedesktop.DBus -> destination=:1.86 serial=6 reply_serial=10 boolean true method call time=1537964753.056974 sender=:1.86 -> destination=org.ofono serial=11 path=/; interface=org.ofono.Manager; member=GetModems method return time=1537964753.057007 sender=:1.62 -> destination=:1.86 serial=95 reply_serial=11 array [ struct { object path "/hfp/org/bluez/hci0/dev_D8_5F_2A_5B_7B_E6" array [ dict entry( string "Online" variant boolean true ) dict entry( string "Powered" variant boolean true ) dict entry( string "Lockdown" variant boolean false ) dict entry( string "Emergency" variant boolean false ) dict entry( string "Serial" variant string "D8:5F:2A:5B:7B:E6" ) dict entry( string "Interfaces" variant array [ string "org.ofono.VoiceCallManager" string "org.ofono.CallVolume" string "org.ofono.Handsfree" string "org.ofono.NetworkRegistration" ] ) dict entry( string "Features" variant array [ string "net" ] ) dict entry( string "Name" variant string "Samsung Galaxy S7" ) dict entry( string "Type" variant string "hfp" ) ] } struct { object path "/phonesim" array [ dict entry( string "Online" variant boolean false ) dict entry( string "Powered" variant boolean false ) dict entry( string "Lockdown" variant boolean false ) dict entry( string "Emergency" variant boolean false ) dict entry( string "Interfaces" variant array [ ] ) dict entry( string "Features" variant array [ ] ) dict entry( string "Type" variant string "hardware" ) ] } ] method call time=1537964753.060383 sender=:1.86 -> destination=org.freedesktop.DBus serial=12 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=RemoveMatch string "type='signal',sender='org.ofono',path='/',interface='org.ofono.Manager',member='ModemAdded'" method call time=1537964753.060427 sender=:1.86 -> destination=org.freedesktop.DBus serial=13 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=RemoveMatch string "type='signal',sender='org.ofono',path='/',interface='org.ofono.Manager',member='ModemRemoved'" method call time=1537964753.060471 sender=:1.86 -> destination=org.freedesktop.DBus serial=14 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=RemoveMatch string "type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0='org.ofono'" method call time=1537964753.060517 sender=:1.86 -> destination=org.freedesktop.DBus serial=15 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=RemoveMatch string "type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0='org.ofono'" method call time=1537964753.060564 sender=:1.86 -> destination=org.freedesktop.DBus serial=16 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=RemoveMatch string "type='signal',sender='org.freedesktop.DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged',arg0='org.freedesktop.DBus'" error time=1537964753.060621 sender=org.freedesktop.DBus -> destination=:1.86 error_name=org.freedesktop.DBus.Error.MatchRuleNotFound reply_serial=16 string "The given match rule wasn't found and can't be removed"At the end we get,
error_name=org.freedesktop.DBus.Error.MatchRuleNotFound reply_serial=16 string "The given match rule wasn't found and can't be removed"In the constructor of the QOfonoManager, the following is happening:
QOfonoManager::QOfonoManager(QObject *parent) : QObject(parent), d_ptr(new Private) { QOfonoDbusTypes::registerObjectPathProperties(); QDBusConnection systemBus(QDBusConnection::systemBus()); QDBusServiceWatcher *ofonoWatcher = new QDBusServiceWatcher("org.ofono", systemBus, QDBusServiceWatcher::WatchForRegistration | QDBusServiceWatcher::WatchForUnregistration, this); connect(ofonoWatcher, SIGNAL(serviceRegistered(QString)), this, SLOT(connectToOfono(QString))); connect(ofonoWatcher, SIGNAL(serviceUnregistered(QString)), this, SLOT(ofonoUnregistered(QString))); if (systemBus.interface()->isServiceRegistered("org.ofono")) { connectToOfono(QString()); } }(full code: https://github.com/ubports/libqofono/blob/xenial/src/qofonomanager.cpp)
So it seems like there is something going on with dbus, but I am not exactly sure what. The constructor I gave you begins to cause it. Could it maybe be a bug in libqofono-0.92 ? Second opinion or guidance is much appreciated. Thanks in advance.