diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index bee7cbc..ba17fc5 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -99,10 +99,12 @@
 /* libata-acpi.c */
 #ifdef CONFIG_ATA_ACPI
 extern void ata_acpi_associate(struct ata_host *host);
+extern int ata_acpi_on_suspend(struct ata_port *ap);
 extern void ata_acpi_on_resume(struct ata_port *ap);
 extern int ata_acpi_on_devcfg(struct ata_device *adev);
 #else
 static inline void ata_acpi_associate(struct ata_host *host) { }
+static inline int ata_acpi_on_suspend(struct ata_port *ap) { return 0; }
 static inline void ata_acpi_on_resume(struct ata_port *ap) { }
 static inline int ata_acpi_on_devcfg(struct ata_device *adev) { return 0; }
 #endif