diff --git a/sys/compat/linuxkpi/common/include/linux/vgaarb.h b/sys/compat/linuxkpi/common/include/linux/vgaarb.h
--- a/sys/compat/linuxkpi/common/include/linux/vgaarb.h
+++ b/sys/compat/linuxkpi/common/include/linux/vgaarb.h
@@ -239,16 +239,43 @@
  * by userspace since we some older X servers have issues.
  */
 #if defined(CONFIG_VGA_ARB)
+#if defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51501
+int vga_client_register(struct pci_dev *pdev,
+			unsigned int (*set_vga_decode)(struct pci_dev *pdev, bool state));
+#elif defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51500
+int vga_client_register(struct pci_dev *pdev, void *cookie,
+			unsigned int (*set_vga_decode)(void *cookie, bool state));
+#else
 int vga_client_register(struct pci_dev *pdev, void *cookie,
 			void (*irq_set_state)(void *cookie, bool state),
 			unsigned int (*set_vga_decode)(void *cookie, bool state));
+#endif
+#else
+#if defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51501
+static inline int vga_client_register(struct pci_dev *pdev,
+				      unsigned int (*set_vga_decode)(struct pci_dev *pdev, bool state))
+#elif defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51500
+static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
+				      unsigned int (*set_vga_decode)(void *cookie, bool state))
 #else
 static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
 				      void (*irq_set_state)(void *cookie, bool state),
 				      unsigned int (*set_vga_decode)(void *cookie, bool state))
+#endif
 {
 	return 0;
 }
+
+static inline int vga_client_unregister(struct pci_dev *pdev)
+{
+#if defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51501
+	return (vga_client_register(NULL, NULL));
+#elif defined(LINUXKPI_VERSION) && LINUXKPI_VERSION >= 51500
+	return (vga_client_register(NULL, NULL, NULL));
+#else
+	return (vga_client_register(NULL, NULL, NULL, NULL));
+#endif
+}
 #endif
 
 #endif /* _LINUXKPI_LINUX_VGA_H_ */