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
@@ -342,6 +342,7 @@
 	size_t			romlen;
 	struct msi_desc		**msi_desc;
 	char			*path_name;
+	spinlock_t		pcie_cap_lock;
 
 	TAILQ_HEAD(, pci_mmio_region)	mmio;
 };
@@ -1044,6 +1045,30 @@
 	return (error);
 }
 
+static inline int
+pcie_capability_clear_and_set_word(struct pci_dev *dev, int pos,
+    uint16_t clear, uint16_t set)
+{
+	int error;
+	uint16_t v;
+
+	if (pos == PCI_EXP_LNKCTL || pos == PCI_EXP_RTCTL)
+		spin_lock(&dev->pcie_cap_lock);
+
+	error = pcie_capability_read_word(dev, pos, &v);
+	if (error == 0) {
+		v &= ~clear;
+		v |= set;
+		error = pcie_capability_write_word(dev, pos, v);
+	}
+
+	if (pos == PCI_EXP_LNKCTL || pos == PCI_EXP_RTCTL)
+		spin_unlock(&dev->pcie_cap_lock);
+
+	return (error);
+}
+
+
 static inline int pcie_get_minimum_link(struct pci_dev *dev,
     enum pci_bus_speed *speed, enum pcie_link_width *width)
 {
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
@@ -524,6 +524,7 @@
 		goto out_dma_init;
 
 	TAILQ_INIT(&pdev->mmio);
+	spin_lock_init(&pdev->pcie_cap_lock);
 
 	spin_lock(&pci_lock);
 	list_add(&pdev->links, &pci_devices);