Index: linux-2.6.16/drivers/ata/libata-core.c
===================================================================
--- linux-2.6.16.orig/drivers/ata/libata-core.c	2006-10-10 19:40:35.000000000 +0200
+++ linux-2.6.16/drivers/ata/libata-core.c	2006-10-10 19:40:48.000000000 +0200
@@ -4122,7 +4122,8 @@
 
 fsm_start:
 	DPRINTK("ata%u: protocol %d task_state %d (dev_stat 0x%X)\n",
-		ap->id, qc->tf.protocol, ap->hsm_task_state, status);
+		ap->id, qc->tf.protocol, ap->hsm_task_state, status,
+		qc->tf.flags & ATA_TFLAG_POLLING);
 
 	switch (ap->hsm_task_state) {
 	case HSM_ST_FIRST:
@@ -4712,6 +4713,14 @@
 		}
 	}
 
+	/* Some controllers show flaky interrupt behavior after
+	 * setting xfer mode.  Use polling instead.
+	 */
+	if (unlikely(qc->tf.command == ATA_CMD_SET_FEATURES &&
+		     qc->tf.feature == SETFEATURES_XFER) &&
+	    (ap->flags & ATA_FLAG_SETXFER_POLLING))
+		qc->tf.flags |= ATA_TFLAG_POLLING;
+
 	/* select the device */
 	ata_dev_select(ap, qc->dev->devno, 1, 0);
 
Index: linux-2.6.16/drivers/ata/pata_via.c
===================================================================
--- linux-2.6.16.orig/drivers/ata/pata_via.c	2006-10-10 19:40:35.000000000 +0200
+++ linux-2.6.16/drivers/ata/pata_via.c	2006-10-10 19:42:43.000000000 +0200
@@ -398,7 +398,7 @@
 
 	.data_xfer	= ata_pio_data_xfer,
 
-	.irq_handler	= pata_via_interrupt,
+	.irq_handler	= ata_interrupt,
 	.irq_clear	= ata_bmdma_irq_clear,
 
 	.port_start	= ata_port_start,
@@ -433,7 +433,7 @@
 
 	.data_xfer	= ata_pio_data_xfer_noirq,
 
-	.irq_handler	= pata_via_interrupt,
+	.irq_handler	= ata_interrupt,
 	.irq_clear	= ata_bmdma_irq_clear,
 
 	.port_start	= ata_port_start,
@@ -455,7 +455,8 @@
 	/* Early VIA without UDMA support */
 	static struct ata_port_info via_mwdma_info = {
 		.sht = &via_sht,
-		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
+		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST |
+			 ATA_FLAG_SETXFER_POLLING,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
 		.port_ops = &via_port_ops
@@ -463,7 +464,8 @@
 	/* Ditto with IRQ masking required */
 	static struct ata_port_info via_mwdma_info_borked = {
 		.sht = &via_sht,
-		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
+		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST |
+			 ATA_FLAG_SETXFER_POLLING,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
 		.port_ops = &via_port_ops_noirq,
@@ -471,7 +473,8 @@
 	/* VIA UDMA 33 devices (and borked 66) */
 	static struct ata_port_info via_udma33_info = {
 		.sht = &via_sht,
-		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
+		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST |
+			 ATA_FLAG_SETXFER_POLLING,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
 		.udma_mask = 0x7,
@@ -480,7 +483,8 @@
 	/* VIA UDMA 66 devices */
 	static struct ata_port_info via_udma66_info = {
 		.sht = &via_sht,
-		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
+		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST |
+			 ATA_FLAG_SETXFER_POLLING,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
 		.udma_mask = 0x1f,
@@ -489,7 +493,8 @@
 	/* VIA UDMA 100 devices */
 	static struct ata_port_info via_udma100_info = {
 		.sht = &via_sht,
-		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
+		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST |
+			 ATA_FLAG_SETXFER_POLLING,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
 		.udma_mask = 0x3f,
@@ -498,7 +503,8 @@
 	/* UDMA133 with bad AST (All current 133) */
 	static struct ata_port_info via_udma133_info = {
 		.sht = &via_sht,
-		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST,
+		.flags = ATA_FLAG_SLAVE_POSS | ATA_FLAG_SRST |
+			 ATA_FLAG_SETXFER_POLLING,
 		.pio_mask = 0x1f,
 		.mwdma_mask = 0x07,
 		.udma_mask = 0x7f,	/* FIXME: should check north bridge */
Index: linux-2.6.16/include/linux/libata.h
===================================================================
--- linux-2.6.16.orig/include/linux/libata.h	2006-10-10 19:40:54.000000000 +0200
+++ linux-2.6.16/include/linux/libata.h	2006-10-10 19:41:00.000000000 +0200
@@ -178,6 +178,7 @@
 	ATA_FLAG_DEBUGMSG	= (1 << 13),
 	ATA_FLAG_DETECT_POLLING	= (1 << 14), /* detect device presence by
 					      * polling IDENTIFY */
+	ATA_FLAG_SETXFER_POLLING= (1 << 14), /* use polling for SETXFER */
 
 	/* The following flag belongs to ap->pflags but is kept in
 	 * ap->flags because it's referenced in many LLDs and will be