diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 1799233..9a547ca 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -50,6 +50,7 @@
 	AHCI_CMD_SLOT_SZ	= 32 * 32,
 	AHCI_RX_FIS_SZ		= 256,
 	AHCI_CMD_TBL_HDR	= 0x80,
+	AHCI_CMD_TBL_CDB	= 0x40,
 	AHCI_CMD_TBL_SZ		= AHCI_CMD_TBL_HDR + (AHCI_MAX_SG * 16),
 	AHCI_PORT_PRIV_DMA_SZ	= AHCI_CMD_SLOT_SZ + AHCI_CMD_TBL_SZ +
 				  AHCI_RX_FIS_SZ,
@@ -510,7 +511,8 @@
 
 static void ahci_qc_prep(struct ata_queued_cmd *qc)
 {
-	struct ahci_port_priv *pp = qc->ap->private_data;
+	struct ata_port *ap = qc->ap;
+	struct ahci_port_priv *pp = ap->private_data;
 	u32 opts;
 	const u32 cmd_fis_len = 5; /* five dwords */
 
@@ -522,18 +524,8 @@
 	opts = (qc->n_elem << 16) | cmd_fis_len;
 	if (qc->tf.flags & ATA_TFLAG_WRITE)
 		opts |= AHCI_CMD_WRITE;
-
-	switch (qc->tf.protocol) {
-	case ATA_PROT_ATAPI:
-	case ATA_PROT_ATAPI_NODATA:
-	case ATA_PROT_ATAPI_DMA:
+	if (is_atapi_taskfile(&qc->tf))
 		opts |= AHCI_CMD_ATAPI;
-		break;
-
-	default:
-		/* do nothing */
-		break;
-	}
 
 	pp->cmd_slot[0].opts = cpu_to_le32(opts);
 	pp->cmd_slot[0].status = 0;
@@ -545,6 +537,10 @@
 	 * a SATA Register - Host to Device command FIS.
 	 */
 	ata_tf_to_fis(&qc->tf, pp->cmd_tbl, 0);
+	if (opts & AHCI_CMD_ATAPI) {
+		memset(pp->cmd_tbl + AHCI_CMD_TBL_CDB, 0, 32);
+		memcpy(pp->cmd_tbl + AHCI_CMD_TBL_CDB, qc->cdb, ap->cdb_len);
+	}
 
 	if (!(qc->flags & ATA_QCFLAG_DMAMAP))
 		return;