diff --git a/sys/compat/linuxkpi/common/include/linux/pci.h b/sys/compat/linuxkpi/common/include/linux/pci.h
--- a/sys/compat/linuxkpi/common/include/linux/pci.h
+++ b/sys/compat/linuxkpi/common/include/linux/pci.h
@@ -355,7 +355,6 @@
 	TAILQ_HEAD(, pci_mmio_region)	mmio;
 };
 
-int pci_request_region(struct pci_dev *pdev, int bar, const char *res_name);
 int pci_alloc_irq_vectors(struct pci_dev *pdev, int minv, int maxv,
     unsigned int flags);
 bool pci_device_is_present(struct pci_dev *pdev);
@@ -369,7 +368,9 @@
 void linuxkpi_pci_iounmap(struct pci_dev *pdev, void *res);
 int linuxkpi_pcim_iomap_regions(struct pci_dev *pdev, uint32_t mask,
     const char *name);
+int linuxkpi_pci_request_region(struct pci_dev *, int, const char *);
 int linuxkpi_pci_request_regions(struct pci_dev *pdev, const char *res_name);
+int linuxkpi_pcim_request_all_regions(struct pci_dev *, const char *);
 void linuxkpi_pci_release_region(struct pci_dev *pdev, int bar);
 void linuxkpi_pci_release_regions(struct pci_dev *pdev);
 int linuxkpi_pci_enable_msix(struct pci_dev *pdev, struct msix_entry *entries,
@@ -562,12 +563,16 @@
 	return (pdev->bus->self);
 }
 
+#define	pci_request_region(pdev, bar, res_name)				\
+    linuxkpi_pci_request_region(pdev, bar, res_name)
 #define	pci_release_region(pdev, bar)					\
     linuxkpi_pci_release_region(pdev, bar)
-#define	pci_release_regions(pdev)					\
-    linuxkpi_pci_release_regions(pdev)
 #define	pci_request_regions(pdev, res_name)				\
     linuxkpi_pci_request_regions(pdev, res_name)
+#define	pci_release_regions(pdev)					\
+    linuxkpi_pci_release_regions(pdev)
+#define	pcim_request_all_regions(pdev, name)				\
+    linuxkpi_pcim_request_all_regions(pdev, name)
 
 static inline void
 lkpi_pci_disable_msix(struct pci_dev *pdev)
diff --git a/sys/compat/linuxkpi/common/src/linux_pci.c b/sys/compat/linuxkpi/common/src/linux_pci.c
--- a/sys/compat/linuxkpi/common/src/linux_pci.c
+++ b/sys/compat/linuxkpi/common/src/linux_pci.c
@@ -1159,8 +1159,9 @@
 	return (rle->count);
 }
 
-int
-pci_request_region(struct pci_dev *pdev, int bar, const char *res_name)
+static int
+lkpi_pci_request_region(struct pci_dev *pdev, int bar, const char *res_name,
+    bool managed)
 {
 	struct resource *res;
 	struct pci_devres *dr;
@@ -1168,9 +1169,20 @@
 	int rid;
 	int type;
 
+	if (!lkpi_pci_bar_id_valid(bar))
+		return (-EINVAL);
+
+	/*
+	 * If the bar is not valid, return success without adding the BAR;
+	 * otherwise linuxkpi_pcim_request_all_regions() will error.
+	 */
+	if (pci_resource_len(pdev, bar) == 0)
+		return (0);
+	/* Likewise if it is neither IO nor MEM, nothing to do for us. */
 	type = pci_resource_type(pdev, bar);
 	if (type < 0)
-		return (-ENODEV);
+		return (0);
+
 	rid = PCIR_BAR(bar);
 	res = bus_alloc_resource_any(pdev->dev.bsddev, type, &rid,
 	    RF_ACTIVE|RF_SHAREABLE);
@@ -1183,11 +1195,16 @@
 
 	/*
 	 * It seems there is an implicit devres tracking on these if the device
-	 * is managed; otherwise the resources are not automatiaclly freed on
-	 * FreeBSD/LinuxKPI tough they should be/are expected to be by Linux
-	 * drivers.
+	 * is managed (lkpi_pci_devres_find() case); otherwise the resources are
+	 * not automatically freed on FreeBSD/LinuxKPI though they should be/are
+	 * expected to be by Linux drivers.
+	 * Otherwise if we are called from a pcim-function with the managed
+	 * argument set, we need to track devres independent of pdev->managed.
 	 */
-	dr = lkpi_pci_devres_find(pdev);
+	if (managed)
+		dr = lkpi_pci_devres_get_alloc(pdev);
+	else
+		dr = lkpi_pci_devres_find(pdev);
 	if (dr != NULL) {
 		dr->region_mask |= (1 << bar);
 		dr->region_table[bar] = res;
@@ -1203,6 +1220,12 @@
 	return (0);
 }
 
+int
+linuxkpi_pci_request_region(struct pci_dev *pdev, int bar, const char *res_name)
+{
+	return (lkpi_pci_request_region(pdev, bar, res_name, false));
+}
+
 int
 linuxkpi_pci_request_regions(struct pci_dev *pdev, const char *res_name)
 {
@@ -1219,6 +1242,24 @@
 	return (0);
 }
 
+int
+linuxkpi_pcim_request_all_regions(struct pci_dev *pdev, const char *res_name)
+{
+	int bar, error;
+
+	for (bar = 0; bar <= PCIR_MAX_BAR_0; bar++) {
+		error = lkpi_pci_request_region(pdev, bar, res_name, true);
+		if (error != 0) {
+			device_printf(pdev->dev.bsddev, "%s: bar %d res_name '%s': "
+			    "lkpi_pci_request_region returned %d\n", __func__,
+			    bar, res_name, error);
+			pci_release_regions(pdev);
+			return (error);
+		}
+	}
+	return (0);
+}
+
 void
 linuxkpi_pci_release_region(struct pci_dev *pdev, int bar)
 {