diff --git a/drivers/ide/cmd64x.c b/drivers/ide/cmd64x.c
index 680e597..ca0c46f 100644
--- a/drivers/ide/cmd64x.c
+++ b/drivers/ide/cmd64x.c
@@ -379,7 +379,8 @@
 		.enablebits	= {{0x00,0x00,0x00}, {0x51,0x08,0x08}},
 		.port_ops	= &cmd64x_port_ops,
 		.host_flags	= IDE_HFLAG_CLEAR_SIMPLEX |
-				  IDE_HFLAG_ABUSE_PREFETCH,
+				  IDE_HFLAG_ABUSE_PREFETCH |
+				  IDE_HFLAG_SERIALIZE,
 		.pio_mask	= ATA_PIO5,
 		.mwdma_mask	= ATA_MWDMA2,
 		.udma_mask	= 0x00, /* no udma */
@@ -389,7 +390,8 @@
 		.init_chipset	= init_chipset_cmd64x,
 		.enablebits	= {{0x51,0x04,0x04}, {0x51,0x08,0x08}},
 		.port_ops	= &cmd648_port_ops,
-		.host_flags	= IDE_HFLAG_ABUSE_PREFETCH,
+		.host_flags	= IDE_HFLAG_ABUSE_PREFETCH |
+				  IDE_HFLAG_SERIALIZE,
 		.pio_mask	= ATA_PIO5,
 		.mwdma_mask	= ATA_MWDMA2,
 		.udma_mask	= ATA_UDMA2,