Receive voip calls while in suspend

There is one approach to use calls or SMS to wake up the phone https://forums.puri.sm/t/librem5-wake-on-im/26613 this can be a temporary work around, but we need a way to wake phone via modem data connection. Anyone knows of issues already filed for this ?

@Guido shared this in xmpp/matrix group: All devices (that can reliably suspend) can support the initial, timer based approach for push notifications (see https://gitlab.gnome.org/guidog/meta-phosh/-/issues/3). Once that is there people can work on device specific support, we have plans for several devices but at least I'm not targeting the L5 (although it would be fun). It would basically use the same logic that would be used to blink the LED in suspend on the L5. So getting the M4 core into shape on the L5 would be good groundwork.

FLX1 use a different power save strategy (keep only a single core of the processor running) so this does not affect FLX1.