diff --git a/drivers/ide/pci/hpt366.c b/drivers/ide/pci/hpt366.c
index 9fce25bdec8a..edb267c78afc 100644
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -1,5 +1,5 @@
 /*
- * linux/drivers/ide/pci/hpt366.c		Version 1.22	Dec 4, 2007
+ * linux/drivers/ide/pci/hpt366.c		Version 1.23	Dec 7, 2007
  *
  * Copyright (C) 1999-2003		Andre Hedrick <andre@linux-ide.org>
  * Portions Copyright (C) 2001	        Sun Microsystems, Inc.
@@ -689,19 +689,17 @@ static void hpt36x_set_mode(ide_drive_t *drive, const u8 speed)
 	struct hpt_info	*info	= pci_get_drvdata(dev);
 	u8  itr_addr		= drive->dn ? 0x44 : 0x40;
 	u32 old_itr		= 0;
-	u32 itr_mask, new_itr;
-
-	itr_mask = speed < XFER_MW_DMA_0 ? 0x30070000 :
-		  (speed < XFER_UDMA_0   ? 0xc0070000 : 0xc03800ff);
-
-	new_itr = get_speed_setting(speed, info);
+	u32 new_itr		= get_speed_setting(speed, info);
+	u32 itr_mask		= speed < XFER_MW_DMA_0 ? 0xc1f8ffff :
+				 (speed < XFER_UDMA_0   ? 0x303800ff :
+							  0x30070000);
 
+	pci_read_config_dword(dev, itr_addr, &old_itr);
+	new_itr = (old_itr & ~itr_mask) | (new_itr & itr_mask);
 	/*
 	 * Disable on-chip PIO FIFO/buffer (and PIO MST mode as well)
 	 * to avoid problems handling I/O errors later
 	 */
-	pci_read_config_dword(dev, itr_addr, &old_itr);
-	new_itr  = (new_itr & ~itr_mask) | (old_itr & itr_mask);
 	new_itr &= ~0xc0000000;
 
 	pci_write_config_dword(dev, itr_addr, new_itr);
@@ -714,16 +712,14 @@ static void hpt37x_set_mode(ide_drive_t *drive, const u8 speed)
 	struct hpt_info	*info	= pci_get_drvdata(dev);
 	u8  itr_addr		= 0x40 + (drive->dn * 4);
 	u32 old_itr		= 0;
-	u32 itr_mask, new_itr;
-
-	itr_mask = speed < XFER_MW_DMA_0 ? 0x303c0000 :
-		  (speed < XFER_UDMA_0   ? 0xc03c0000 : 0xc1c001ff);
-
-	new_itr = get_speed_setting(speed, info);
+	u32 new_itr		= get_speed_setting(speed, info);
+	u32 itr_mask		= speed < XFER_MW_DMA_0 ? 0xcfc3ffff :
+				 (speed < XFER_UDMA_0   ? 0x31c001ff :
+							  0x303c0000);
 
 	pci_read_config_dword(dev, itr_addr, &old_itr);
-	new_itr = (new_itr & ~itr_mask) | (old_itr & itr_mask);
-	
+	new_itr = (old_itr & ~itr_mask) | (new_itr & itr_mask);
+
 	if (speed < XFER_MW_DMA_0)
 		new_itr &= ~0x80000000; /* Disable on-chip PIO FIFO/buffer */
 	pci_write_config_dword(dev, itr_addr, new_itr);