Index: head/sys/dev/pci/pci_pci.c
===================================================================
--- head/sys/dev/pci/pci_pci.c
+++ head/sys/dev/pci/pci_pci.c
@@ -918,6 +918,7 @@
 pcib_probe_hotplug(struct pcib_softc *sc)
 {
 	device_t dev;
+	uint16_t link_sta, slot_sta;
 
 	if (!pci_enable_pcie_hp)
 		return;
@@ -932,15 +933,29 @@
 	sc->pcie_link_cap = pcie_read_config(dev, PCIER_LINK_CAP, 4);
 	sc->pcie_slot_cap = pcie_read_config(dev, PCIER_SLOT_CAP, 4);
 
+	if ((sc->pcie_slot_cap & PCIEM_SLOT_CAP_HPC) == 0)
+		return;
+
 	/*
-	 * XXX: Handling of slots with a power controller needs to be
-	 * reexamined.  Ignore hotplug on such slots for now.
+	 * Some devices report that they have an MRL when they actually
+	 * do not.  Since they always report that the MRL is open, child
+	 * devices would be ignored.  Try to detect these devices and
+	 * ignore their claim of HotPlug support.
+	 *
+	 * If there is an open MRL but the Data Link Layer is active,
+	 * the MRL is not real.
 	 */
-	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_PCP)
-		return;
-	
-	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_HPC)
-		sc->flags |= PCIB_HOTPLUG;
+	if ((sc->pcie_slot_cap & PCIEM_SLOT_CAP_MRLSP) != 0 &&
+	    (sc->pcie_link_cap & PCIEM_LINK_CAP_DL_ACTIVE) != 0) {
+		link_sta = pcie_read_config(dev, PCIER_LINK_STA, 2);
+		slot_sta = pcie_read_config(dev, PCIER_SLOT_STA, 2);
+		if ((slot_sta & PCIEM_SLOT_STA_MRLSS) != 0 &&
+		    (link_sta & PCIEM_LINK_STA_DL_ACTIVE) != 0) {
+			return;
+		}
+	}
+
+	sc->flags |= PCIB_HOTPLUG;
 }
 
 /*
@@ -966,6 +981,8 @@
 	new = (ctl & ~mask) | val;
 	if (new == ctl)
 		return;
+	if (bootverbose)
+		device_printf(dev, "HotPlug command: %04x -> %04x\n", ctl, new);
 	pcie_write_config(dev, PCIER_SLOT_CTL, new, 2);
 	if (!(sc->pcie_slot_cap & PCIEM_SLOT_CAP_NCCS) &&
 	    (ctl & new) & PCIEM_SLOT_CTL_CCIE) {
@@ -1028,9 +1045,6 @@
 static int
 pcib_hotplug_present(struct pcib_softc *sc)
 {
-	device_t dev;
-
-	dev = sc->dev;
 
 	/* Card must be inserted. */
 	if (!pcib_hotplug_inserted(sc))
@@ -1059,7 +1073,7 @@
 {
 	bool card_inserted, ei_engaged;
 
-	/* Clear DETACHING if Present Detect has cleared. */
+	/* Clear DETACHING if Presence Detect has cleared. */
 	if ((sc->pcie_slot_sta & (PCIEM_SLOT_STA_PDC | PCIEM_SLOT_STA_PDS)) ==
 	    PCIEM_SLOT_STA_PDC)
 		sc->flags &= ~PCIB_DETACHING;
@@ -1101,14 +1115,15 @@
 
 	/*
 	 * Start a timer to see if the Data Link Layer times out.
-	 * Note that we only start the timer if Presence Detect
+	 * Note that we only start the timer if Presence Detect or MRL Sensor
 	 * changed on this interrupt.  Stop any scheduled timer if
 	 * the Data Link Layer is active.
 	 */
 	if (sc->pcie_link_cap & PCIEM_LINK_CAP_DL_ACTIVE) {
 		if (card_inserted &&
 		    !(sc->pcie_link_sta & PCIEM_LINK_STA_DL_ACTIVE) &&
-		    sc->pcie_slot_sta & PCIEM_SLOT_STA_PDC) {
+		    sc->pcie_slot_sta &
+		    (PCIEM_SLOT_STA_MRLSC | PCIEM_SLOT_STA_PDC)) {
 			if (cold)
 				device_printf(sc->dev,
 				    "Data Link Layer inactive\n");
@@ -1144,6 +1159,10 @@
 	/* Clear the events just reported. */
 	pcie_write_config(dev, PCIER_SLOT_STA, sc->pcie_slot_sta, 2);
 
+	if (bootverbose)
+		device_printf(dev, "HotPlug interrupt: %#x\n",
+		    sc->pcie_slot_sta);
+
 	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_ABP) {
 		if (sc->flags & PCIB_DETACH_PENDING) {	
 			device_printf(dev,
@@ -1165,7 +1184,7 @@
 		    sc->pcie_slot_sta & PCIEM_SLOT_STA_MRLSS ? "open" :
 		    "closed");
 	if (bootverbose && sc->pcie_slot_sta & PCIEM_SLOT_STA_PDC)
-		device_printf(dev, "Present Detect Changed to %s\n",
+		device_printf(dev, "Presence Detect Changed to %s\n",
 		    sc->pcie_slot_sta & PCIEM_SLOT_STA_PDS ? "card present" :
 		    "empty");
 	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_CC)
@@ -1234,7 +1253,7 @@
 	sta = pcie_read_config(dev, PCIER_SLOT_STA, 2);
 	if (!(sta & PCIEM_SLOT_STA_CC)) {
 		device_printf(dev,
-		    "Hotplug Command Timed Out - forcing detach\n");
+		    "HotPlug Command Timed Out - forcing detach\n");
 		sc->flags &= ~(PCIB_HOTPLUG_CMD_PENDING | PCIB_DETACH_PENDING);
 		sc->flags |= PCIB_DETACHING;
 		pcib_pcie_hotplug_update(sc, 0, 0, true);