diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
--- a/drivers/scsi/sata_mv.c
+++ b/drivers/scsi/sata_mv.c
@@ -409,14 +409,8 @@ static void mv_irq_clear(struct ata_port
 static void mv_start_dma(void __iomem *base, struct mv_port_priv *pp,
 			 struct ata_port *ap)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&ap->host_set->lock, flags);
-	
 	writelfl(EDMA_EN, base + EDMA_CMD_OFS);
 	pp->pp_flags |= MV_PP_FLAG_EDMA_EN;
-
-	spin_unlock_irqrestore(&ap->host_set->lock, flags);
 }
 
 static void mv_stop_dma(struct ata_port *ap)