mmdbus: improve eSIM detection using EID and handle missing slot paths

Without proper eSIM detection, EVE cannot identify that the active slot is
an eSIM and remains stuck on the unsupported eSIM slot instead of
automatically switching to a physical SIM slot.

ModemManager often fails to report SIM slot types (SIMPropertyType returns
"unknown"/unspecified), making it impossible to distinguish eSIM from physical
SIM. Improve detection by querying the EID (eUICC Identifier) — only eSIM
chips carry one, so its presence reliably identifies an eSIM.

Additionally, ModemPropertySIMSlots returns empty D-Bus paths for slots with
no SIM or no active eSIM profile. For the currently active slot, fall back to
ModemPropertySIM which often still provides a valid object even when the slot
array entry is empty.

Unify SIM presence detection for unknown and physical SIM types: use the
slot array path (hasSlotPath) as the common presence indicator instead of
checking ICCID for unknown types separately.

In preferPhysSimOverESim, prefer a confirmed physical slot over an
unspecified-type candidate. When the active slot is a detected eSIM, it is
very unlikely for a modem to have multiple eUICCs, so the remaining slots
with unknown type are almost certainly physical — but only used as a fallback.

Signed-off-by: Milan Lenco <milan@zededa.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

pkg/wwan/mmagent/mmdbus/client.go

@@ -553,12 +553,23 @@ func (c *Client) getModemStatus(modemObj dbus.BusObject) (
 	for i, simPath := range simSlots {
 		slot := uint8(i + 1)
 		isPrimary := uint32(slot) == primarySIM
+		// ModemPropertySIMSlots returns empty (root "/") D-Bus paths for slots
+		// with no SIM inserted or no active eSIM profile. Record whether the slot
+		// had a valid path before we attempt the fallback below.
+		hasSlotPath := simPath.IsValid() && len(simPath) > 1
 		simCard := types.WwanSimCard{
 			SlotNumber:    slot,
 			SlotActivated: isPrimary,
 			Type:          types.SimTypeUnspecified,
 			State:         SIMStateAbsent,
 		}
+		// ModemPropertySIMSlots may return an empty path for the active slot
+		// (e.g. eSIM with no profile), but ModemPropertySIM often still provides
+		// a valid object. Fall back to it so we can query SIM properties (EID,
+		// ICCID, etc.) for the active slot even when the slot array is incomplete.
+		if isPrimary && !hasSlotPath {
+			_ = getDBusProperty(c, modemObj, ModemPropertySIM, &simPath)
+		}
 		if simPath.IsValid() && len(simPath) > 1 {
 			simPaths = append(simPaths, string(simPath))
 			simObj := c.conn.Object(MMInterface, simPath)
@@ -568,31 +579,27 @@ func (c *Client) getModemStatus(modemObj dbus.BusObject) (
 			_ = getDBusProperty(c, simObj, SIMPropertyIMSI, &simCard.IMSI)
 			var simType uint32
 			_ = getDBusProperty(c, simObj, SIMPropertyType, &simType)
+			// ModemManager often reports SIMPropertyType as "unknown" even for
+			// eSIMs. Improve detection by checking for an EID (eUICC Identifier).
+			// Only eSIM chips have one, so its presence is a reliable indicator.
+			var eid string
+			_ = getDBusProperty(c, simObj, SIMPropertyEID, &eid)
+			if simType == SIMTypeUnknown && eid != "" {
+				simType = SIMTypeESIM
+			}
 			switch simType {
-			case SIMTypeUnknown:
-				// If the SIM type is not recognized, consider SIM card as present
-				// if ICCID is not empty.
-				if simCard.ICCID != "" {
-					simCard.State = SIMStatePresent
-				}
-			case SIMTypeESIM:
-				// eSIM is not supported by EVE (or even by ModemManager) for connection
-				// establishment, but we still want to at least publish correct status
-				// information for the eSIM "slot".
-				simCard.Type = types.SimTypeEmbedded
-				var esimStatus uint32
-				_ = getDBusProperty(c, simObj, SIMPropertyESIMStatus, &esimStatus)
-				if esimStatus == ESIMWithProfiles {
-					simCard.State = SIMStatePresent
-				}
-			case SIMTypePhysical:
-				// Since we have valid dbus object for the physical SIM slot, it means
-				// that the SIM card is present.
-				// But note that even if SIM card is present but the slot is inactive,
-				// ModemManager might report the card as absent, without providing any SIM
-				// object path to work with.
-				// On the other hand, with mbimcli we are able to distinguish between
-				// missing and inactive SIM card:
+			case SIMTypeUnknown, SIMTypePhysical:
+				// For both unknown and physical SIM types, use the presence of
+				// a valid D-Bus path in the slot array (hasSlotPath) as the
+				// indicator of SIM card presence.
+				// Note: for the primary slot we may have obtained the path via
+				// the ModemPropertySIM fallback above, not from the slot array.
+				// In that case hasSlotPath is false, indicating empty SIM slot.
+				//
+				// However, for inactive slots, ModemManager may not provide any SIM
+				// object path even if a card is physically inserted.
+				// With mbimcli we are able to distinguish between missing and
+				// inactive SIM card:
 				//     mbimcli -p -d /dev/cdc-wdm0 --ms-query-slot-info-status 0
 				//     [/dev/cdc-wdm0] Slot info status retrieved:
 				//	          Slot '0': 'state-off'
@@ -616,8 +623,22 @@ func (c *Client) getModemStatus(modemObj dbus.BusObject) (
 				//             Num apps: 0
 				//             Is eUICC: no
 				// TODO: should we call mbimcli/qmicli ?
-				simCard.Type = types.SimTypePhysical
-				simCard.State = SIMStatePresent
+				if simType == SIMTypePhysical {
+					simCard.Type = types.SimTypePhysical
+				}
+				if hasSlotPath {
+					simCard.State = SIMStatePresent
+				}
+			case SIMTypeESIM:
+				// eSIM is not supported by EVE (or even by ModemManager) for connection
+				// establishment, but we still want to at least publish correct status
+				// information for the eSIM "slot".
+				simCard.Type = types.SimTypeEmbedded
+				var esimStatus uint32
+				_ = getDBusProperty(c, simObj, SIMPropertyESIMStatus, &esimStatus)
+				if esimStatus == ESIMWithProfiles {
+					simCard.State = SIMStatePresent
+				}
 			}
 			if !simCard.SlotActivated {
 				simCard.State = SIMStateInactive
@@ -1623,19 +1644,32 @@ func (c *Client) preferPhysSimOverESim(modemObj dbus.BusObject) error {
 		return fmt.Errorf("missing SIM card status for modem: %s", modem.Path)
 	}
 	var usesESim bool
-	var firstPhysSlot uint8 // slots starts with 1 (0 can be used as undefined)
+	var firstPhysSlot uint8          // first confirmed physical slot (0 = none found)
+	var firstCandidatePhysSlot uint8 // first unspecified-type slot (0 = none found)
 	for _, simCard := range modem.Status.SimCards {
 		switch simCard.Type {
 		case types.SimTypePhysical:
 			if firstPhysSlot == 0 || simCard.SlotNumber < firstPhysSlot {
 				firstPhysSlot = simCard.SlotNumber
 			}
+		case types.SimTypeUnspecified:
+			// When the active slot is eSIM, ModemManager often fails to report
+			// types for inactive slots (returns "unknown"). It is very unlikely
+			// for a modem to have multiple eUICCs, so assuming that the other
+			// slots are physical is a safe bet. However, prefer a confirmed
+			// physical slot if one is available.
+			if firstCandidatePhysSlot == 0 || simCard.SlotNumber < firstCandidatePhysSlot {
+				firstCandidatePhysSlot = simCard.SlotNumber
+			}
 		case types.SimTypeEmbedded:
 			if simCard.SlotActivated {
 				usesESim = true
 			}
 		}
 	}
+	if firstPhysSlot == 0 {
+		firstPhysSlot = firstCandidatePhysSlot
+	}
 	if !usesESim || firstPhysSlot == 0 {
 		// Nothing to do.
 		return nil

pkg/wwan/mmagent/mmdbus/mmapi.go

@@ -63,6 +63,7 @@ const (
 	SIMPropertyIMSI       = SIMInterface + ".Imsi"
 	SIMPropertyType       = SIMInterface + ".SimType"
 	SIMPropertyESIMStatus = SIMInterface + ".EsimStatus"
+	SIMPropertyEID        = SIMInterface + ".Eid"
 )
 
 // SIM type