packaging, ims-pdn-up, imsd, README: imsd runs without /etc/imsd.env and idles without a SIM

With the P-CSCF coming from the PDN's PCO, the configuration file has no
required line left, so the apk's ConditionPathExists=/etc/imsd.env drop-in
goes: the unit starts on every phone with the package, and VoLTE is on by
default. Installing the package and inserting a SIM is the opt-in; the file
holds overrides only, and its existence changes nothing. By the versioning
rule (AGENTS §11, the first commit of this series) that is what moves the
major number: the release is 1.0.0, and §11 now records it. What used to be the
file's job — keeping a phone nobody configured out of a failing unit — is now
a rule on facts, the same for every phone: a modem in the failed state with
a SIM reason makes the script write IMSD_IDLE=no-sim to /run/imsd.env and
exit 0; a profile-indexed connect series the network refuses ten times in a
row — each a persistent 3GPP cause in ModemManager's typed error (not
subscribed, unknown APN, barred, not authorised in the PLMN, authentication
failed, the service option not supported, the wrong PDN type) with packet
service at the time; counted only while the modem reads registered,
connecting or connected with packet service not detached — stricter than
the daemon's PacketServiceUp; any other read, a timeout or a transient cause
starts the count again — writes IMSD_IDLE=no-ims-pdn; and a bring-up that
ends with no P-CSCF — none configured, none discovered: no IPv6 P-CSCF read
from the PCO (PCSCF_DISCOVERY=none in the hand-off, the reader's exit 2: the
list absent, empty, unreadable or IPv4/FQDN only), discovery skipped (no
rmnet mux id) or no hand-off at all (a manual run) — and no registration of
imsd's own to resume is the daemon's own idle, decided before it takes the bus name (SaPeer and the
holds' old_gone say what can be resumed; a pair the holds wrote off is taken
out of the kernel there) and at the no-target bring-up, where a pair nothing
can resume is written off and taken out of the kernel first. imsd reads the key, logs idle: … and exits 0, which Restart=on-failure
leaves alone, so the unit stays inactive until the next boot, a systemctl
start or a start of imsd-ofonod where that runs (its Wants starts an idle
imsd again). What is not a fact keeps the retry: no coverage, a SIM still
waiting for its PIN, a modem without an ims profile (the APN-string connect
is tried), an APN-string series (the modem's own wall), a resumable pair
whose attempt failed (the fatal), and a P-CSCF reader that did not answer
(PCSCF_DISCOVERY=failed: the daemon exits 1 and the restart runs discovery
again). A phone that never had the file keeps its stopped unit through the
upgrade and starts at its next boot, registering where the rule above lets
it — at the upgrade itself where imsd-ofonod runs, whose restart pulls imsd
in through its Wants (systemd queues the marked unit's try-restart, collapses
it to a restart and starts what the unit Wants in the same transaction:
job_type_collapse, transaction_add_job_and_dependencies, 262~rc3); the
opt-out is systemctl mask --now imsd, since a plain disable is undone by
that Wants. imsd-ofonod.service loses its After=imsd.service: with imsd
starting on every phone, GNOME Calls' backend would otherwise wait behind
the ims PDN bring-up at every boot and at its marked restart at an upgrade,
for the whole bring-up (up to its TimeoutStartSec=900); it starts at once and republishes when imsd's name
appears (OnImsdAppeared).
The configuration file's path is the IMSD_ENV seam the mock bench uses.
AGENTS §6's lint figures are this tree's (109 findings in 16 of 20 files,
2026-10-13; the 72 of 2026-10-06 predate the Qmi files).

Tested: crafter-build test, 8 passed; on the host build the daemon's idle
exit for the script's keys and, with no pair, for every discovery verdict
but failed (none, skipped, no hand-off) — exit 0 — and the exit 1 for
failed; the script's arms on the mock bench; on the dev phone (KPN), in
builds of this series: the daemon's idle at the no-target bring-up with the
dead pair removed and before the bus name for a pair the holds had written
off, the discovery-failed exit 1 and its restart, the start without the file, the pull-in by an imsd-ofonod restart
and the mask holding against it and a reboot, and imsd-ofonod starting at
once with imsd stopped and republishing when imsd's name appeared.

packaging/APKBUILD.binary

@@ -60,18 +60,17 @@ package() {
     # account created at install — imsd-dialerd owns those session bus names
     install -Dm644 "$srcdir"/org.kde.modem.daemon.desktop \
         "$pkgdir"/etc/skel/.config/autostart/org.kde.modem.daemon.desktop
-    # enabled by preset: the unit is a no-op until /etc/imsd.env exists, and
-    # VoLTE surviving reboots must not depend on a manual systemctl enable
+    # enabled by preset: VoLTE surviving reboots must not depend on a manual
+    # systemctl enable. Since 1.0.0 the unit needs no configuration file (the
+    # P-CSCF comes from the PDN's PCO) and starts on every phone with the
+    # package; without a SIM it exits cleanly and stays inactive (IMSD_IDLE),
+    # and `systemctl mask --now imsd` opts out (a disable is undone by
+    # imsd-ofonod's Wants=imsd.service)
     install -Dm644 "$srcdir"/80-imsd.preset \
         "$pkgdir"/usr/lib/systemd/system-preset/80-imsd.preset
     mkdir -p "$pkgdir"/etc/systemd/system/multi-user.target.wants
     ln -s /usr/lib/systemd/system/imsd.service \
         "$pkgdir"/etc/systemd/system/multi-user.target.wants/imsd.service
-    # ...but only actually start once the carrier config exists, so
-    # unconfigured systems don't boot into a failing unit
-    mkdir -p "$pkgdir"/usr/lib/systemd/system/imsd.service.d
-    printf '[Unit]\nConditionPathExists=/etc/imsd.env\n' \
-        > "$pkgdir"/usr/lib/systemd/system/imsd.service.d/10-require-config.conf
     install -Dm755 imsd-ofonod "$pkgdir"/usr/bin/imsd-ofonod
     install -Dm755 imsd-ofono-restart-calls.sh \
         "$pkgdir"/usr/libexec/imsd-ofono-restart-calls.sh