Index: sys/dev/ata/ata-disk.c
===================================================================
--- sys/dev/ata/ata-disk.c	(revision 211707)
+++ sys/dev/ata/ata-disk.c	(working copy)
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/kernel.h>
 #include <sys/module.h>
 #include <sys/malloc.h>
+#include <sys/reboot.h>
 #include <sys/bio.h>
 #include <sys/bus.h>
 #include <sys/conf.h>
@@ -59,6 +60,7 @@ static int ad_get_geometry(device_t dev);
 static void ad_set_geometry(device_t dev);
 static void ad_done(struct ata_request *request);
 static void ad_describe(device_t dev);
+static int ad_shutdown(struct ata_device *, int);
 static int ad_version(u_int16_t version);
 static disk_strategy_t ad_strategy;
 static disk_ioctl_t ad_ioctl;
@@ -161,6 +163,10 @@ ad_attach(device_t dev)
     device_add_child(dev, "subdisk", device_get_unit(dev));
     bus_generic_attach(dev);
 
+    if ((EVENTHANDLER_REGISTER(shutdown_final, ad_shutdown,
+	atadev, SHUTDOWN_PRI_FIRST)) == NULL)
+	    printf("ad_attach: failed to register shutdown event.\n");
+
     callout_init(&atadev->spindown_timer, 1);
     return 0;
 }
@@ -201,12 +207,13 @@ ad_detach(device_t dev)
 }
 
 static int
-ad_shutdown(device_t dev)
+ad_shutdown(struct ata_device *atadev, int howto)
 {
-    struct ata_device *atadev = device_get_softc(dev);
 
     if (atadev->param.support.command2 & ATA_SUPPORT_FLUSHCACHE)
-	ata_controlcmd(dev, ATA_FLUSHCACHE, 0, 0, 0);
+	ata_controlcmd(atadev->dev, ATA_FLUSHCACHE, 0, 0, 0);
+    if ((howto & RB_POWEROFF) && (atadev->param.support.command1 & ATA_SUPPORT_POWERMGT))
+	ata_controlcmd(atadev->dev, ATA_STANDBY_IMMEDIATE, 0, 0, 0);
     return 0;
 }
 
@@ -591,7 +598,7 @@ static device_method_t ad_methods[] = {
     DEVMETHOD(device_probe,     ad_probe),
     DEVMETHOD(device_attach,    ad_attach),
     DEVMETHOD(device_detach,    ad_detach),
-    DEVMETHOD(device_shutdown,  ad_shutdown),
+    DEVMETHOD(device_shutdown,  bus_generic_shutdown),
 
     /* ATA methods */
     DEVMETHOD(ata_reinit,       ad_reinit),