diff --git a/drivers/ata/pata_legacy.c b/drivers/ata/pata_legacy.c
index 4fe9d21..be81642 100644
--- a/drivers/ata/pata_legacy.c
+++ b/drivers/ata/pata_legacy.c
@@ -542,7 +542,7 @@ static void opti82c46x_set_piomode(struct ata_port *ap, struct ata_device *adev)
 	u8 sysclk;
 
 	/* Get the clock */
-	sysclk = opti_syscfg(0xAC) & 0xC0;	/* BIOS set */
+	sysclk = (opti_syscfg(0xAC) & 0xC0) >> 6;	/* BIOS set */
 
 	/* Enter configuration mode */
 	ioread16(ap->ioaddr.error_addr);