diff -u dist-2.4.3/drivers/ide/hpt366.c linux-2.4/drivers/ide/hpt366.c
--- dist-2.4.3/drivers/ide/hpt366.c	Sat Jan 27 08:45:58 2001
+++ linux-2.4/drivers/ide/hpt366.c	Thu Apr 26 20:15:17 2001
@@ -523,9 +638,11 @@
 
 void hpt370_rw_proc (ide_drive_t *drive, ide_dma_action_t func)
 {
-	if ((func != ide_dma_write) || (func != ide_dma_read))
+	if ((func != ide_dma_write && func != ide_dma_read)
+	 || drive->rwproc_cache == (void *)func)
 		return;
 	hpt370_tune_chipset(drive, drive->current_speed, (func == ide_dma_write));
+	drive->rwproc_cache = (void *)func;
 }
 
 static int config_drive_xfer_rate (ide_drive_t *drive)
diff -u dist-2.4.3/include/linux/ide.h linux-2.4/include/linux/ide.h
--- dist-2.4.3/include/linux/ide.h	Mon Jan 29 23:25:32 2001
+++ linux-2.4/include/linux/ide.h	Thu Apr 26 20:16:00 2001
@@ -284,6 +284,7 @@
 	unsigned long service_time;	/* service time of last request */
 	unsigned long timeout;		/* max time to wait for irq */
 	special_t	special;	/* special action flags */
+	void	 *rwproc_cache;		/* last rwproc update */
 	byte     keep_settings;		/* restore settings after drive reset */
 	byte     using_dma;		/* disk is using dma for read/write */
 	byte     waiting_for_dma;	/* dma currently in progress */