11-16-2020, 05:36 PM
What's your source for that being the order of events on receiving a call? Have you been following a trace, or just observing that the phone wakes, then you see a wifi symbol appear, then the phone eventually starts ringing? I suspect what's happening is that the modem wakes the sleeping CPU, which goes through the same resume-from-suspend process as it would if the power button was pressed. This includes NetworkManager reconnecting Wifi, and ModemManager talking with the modem. As the modem often drops off the USB bus at this point, before reappearing as another device (modem number in ModemManager increments each time this happens) it can take a while before modemmanager finds out there's a call ringing. ModemManager then sends the dbus signal which the Calls app receives, pops up and starts the ring tone. I'm speculating based on how things have worked on earlier linux phones, so if you've got a more recent source I'd be interested.