diff --git a/drivers/ide/pci/it8213.c b/drivers/ide/pci/it8213.c
index 90b52ed..2a0f45c 100644
--- a/drivers/ide/pci/it8213.c
+++ b/drivers/ide/pci/it8213.c
@@ -101,24 +101,11 @@
 	pci_read_config_byte(dev, 0x54, &reg54);
 	pci_read_config_byte(dev, 0x55, &reg55);
 
-	switch(speed) {
-		case XFER_UDMA_6:
-		case XFER_UDMA_4:
-		case XFER_UDMA_2:	u_speed = 2 << (drive->dn * 4); break;
-		case XFER_UDMA_5:
-		case XFER_UDMA_3:
-		case XFER_UDMA_1:	u_speed = 1 << (drive->dn * 4); break;
-		case XFER_UDMA_0:	u_speed = 0 << (drive->dn * 4); break;
-			break;
-		case XFER_MW_DMA_2:
-		case XFER_MW_DMA_1:
-		case XFER_SW_DMA_2:
-			break;
-		default:
-			return;
-	}
-
 	if (speed >= XFER_UDMA_0) {
+		u8 udma = speed - XFER_UDMA_0;
+
+		u_speed = min_t(u8, 2 - (udma & 1), udma) << (drive->dn * 4);
+
 		if (!(reg48 & u_flag))
 			pci_write_config_byte(dev, 0x48, reg48 | u_flag);
 		if (speed >= XFER_UDMA_5) {