Index: FreeBSD/sys/dev/pci/pci_if.m
===================================================================
--- FreeBSD/sys/dev/pci/pci_if.m
+++ FreeBSD/sys/dev/pci/pci_if.m
@@ -60,6 +60,11 @@
 	    PCI_ID_RID,
 	    PCI_ID_MSI,
 	};
+
+	enum pci_feature {
+	    PCI_FEATURE_HP,		/* Hot Plug feature */
+	    PCI_FEATURE_AER,		/* Advanced Error Reporting */
+	};
 }
 
 
Index: FreeBSD/sys/dev/pci/pci_pci.c
===================================================================
--- FreeBSD/sys/dev/pci/pci_pci.c
+++ FreeBSD/sys/dev/pci/pci_pci.c
@@ -76,6 +76,8 @@
 static void		pcib_pcie_cc_timeout(void *arg);
 static void		pcib_pcie_dll_timeout(void *arg);
 #endif
+static int		pcib_request_feature(device_t pcib, device_t dev,
+			    enum pci_feature feature);
 
 static device_method_t pcib_methods[] = {
     /* Device interface */
@@ -119,6 +121,7 @@
     DEVMETHOD(pcib_try_enable_ari,	pcib_try_enable_ari),
     DEVMETHOD(pcib_ari_enabled,		pcib_ari_enabled),
     DEVMETHOD(pcib_decode_rid,		pcib_ari_decode_rid),
+    DEVMETHOD(pcib_request_feature,	pcib_request_feature),
 
     DEVMETHOD_END
 };
@@ -2829,3 +2832,24 @@
 
 	return (0);
 }
+
+/*
+ * Pass the request to use this PCI feature up the tree. Either there's a
+ * firmware like ACPI that's using this feature that will approve (or deny) the
+ * request to take it over. Or the platform has no such firmware, in which case
+ * the request will be approved. If the request is approved, the OS is expected
+ * to make use of the feature or render it harmless.
+ */
+static int
+pcib_request_feature(device_t pcib, device_t dev, enum pci_feature feature)
+{
+	device_t bus;
+
+	/*
+	 * Our parent is necessarily a pci bus. It's parent will either be
+	 * another pci bridge (which passes it up) or a host bridge that can
+	 * approve or reject the request.
+	 */
+	bus = device_get_parent(pcib);
+	return (PCIB_REQUEST_FEATURE(device_get_parent(bus), dev, feature));
+}
Index: FreeBSD/sys/dev/pci/pcib_if.m
===================================================================
--- FreeBSD/sys/dev/pci/pcib_if.m
+++ FreeBSD/sys/dev/pci/pcib_if.m
@@ -46,6 +46,14 @@
 
 		return (0);
 	}
+
+	static int
+	pcib_null_request_feature(device_t pcib, device_t dev,
+	    enum pci_feature f)
+	{
+
+		return (ENXIO);
+	}
 };
 
 HEADER {
@@ -212,3 +220,12 @@
 	int 		*slot;
 	int 		*func;
 } DEFAULT pcib_decode_rid;
+
+#
+# Request control of PCI features from host firmware, if any.
+#
+METHOD int request_feature {
+	device_t	pcib;
+	device_t	dev;
+	enum pci_feature feature;
+} DEFAULT pcib_null_request_feature;