GDM: Report to homed that we support suspend
Split out from #3 (closed)
See the research document for implementation details, but TL;DR:
- check if we have
X-GDM-CanHomedSuspend=true
in the session launcher .desktop file (already implemented in a previous experimental patch) - call
send_environment_variable("SYSTEMD_HOME_SUSPEND", "true", conversation)
before we callgdm_dbus_worker_call_authenticate