[libata] only reset if ATA_FLAG_SATA_RESET is present

drivers/scsi/libata-core.c

@@ -1058,10 +1058,12 @@ void sata_phy_reset(struct ata_port *ap)
 	u32 sstatus;
 	unsigned long timeout = jiffies + (HZ * 5);
 
-	scr_write(ap, SCR_CONTROL, 0x301);	/* issue phy wake/reset */
-	scr_read(ap, SCR_CONTROL);		/* dummy read; flush */
-	udelay(400);				/* FIXME: a guess */
-	scr_write(ap, SCR_CONTROL, 0x300);	/* issue phy wake/reset */
+	if (ap->flags & ATA_FLAG_SATA_RESET) {
+		scr_write(ap, SCR_CONTROL, 0x301); /* issue phy wake/reset */
+		scr_read(ap, SCR_STATUS);	/* dummy read; flush */
+		udelay(400);			/* FIXME: a guess */
+	}
+	scr_write(ap, SCR_CONTROL, 0x300);	/* issue phy wake/clear reset */
 
 	/* wait for phy to become ready, if necessary */
 	do {