Deep suspend on the FP6 is ended every few seconds by the modem's QMI
indications that ModemManager subscribes to: signal info on a 5 dB delta,
system info, DSD system status (16 + 3 of 25 deep cycles on 2026-10-14).
ModemManager already has the answer: started with
--test-quick-suspend-resume it sets the modem "terse" on logind's
PrepareForSleep (those subscriptions off, calls and texts still delivered)
and synchronises on resume. On the dev phone a logind-driven deep cycle
then runs to its 60 s alarm with the modem registered and imsd up, where
none of 21 did before.
Ship the flag as a drop-in. It does nothing while the sleep targets stay
masked, and is the modem side of the suspend policy when they go.
