diff -Nurp linux-2.6.27.orig/drivers/ata/ahci.c linux-2.6.27/drivers/ata/ahci.c
--- linux-2.6.27.orig/drivers/ata/ahci.c	2008-10-09 18:13:53.000000000 -0400
+++ linux-2.6.27/drivers/ata/ahci.c	2008-11-19 12:56:04.000000000 -0500
@@ -1220,7 +1220,7 @@ static void ahci_sw_activity_blink(unsig
 	unsigned long led_message = emp->led_state;
 	u32 activity_led_state;
 
-	led_message &= 0xffff0000;
+	led_message &= 0x00070000;
 	led_message |= ap->port_no | (link->pmp << 8);
 
 	/* check to see if we've had activity.  If so,