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
@@ -1178,6 +1178,7 @@
 static inline int
 pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *dst)
 {
+	*dst = 0;
 	if (pos & 3)
 		return -EINVAL;
 
@@ -1190,6 +1191,7 @@
 static inline int
 pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *dst)
 {
+	*dst = 0;
 	if (pos & 3)
 		return -EINVAL;