asdf

index a441c75..417394b 100644
@@ -1747,6 +1747,7 @@ int ata_bus_probe(struct ata_port *ap)
 	int tries[ATA_MAX_DEVICES];
 	int i, rc, down_xfermask;
 	struct ata_device *dev;
+	int dnxfer_sel;
 
 	ata_port_probe(ap);
 

@@ -1828,13 +1829,15 @@ int ata_bus_probe(struct ata_port *ap)
 		/* fall through */
 	default:
 		tries[dev->devno]--;
-		if (down_xfermask &&
-		    ata_down_xfermask_limit(dev, tries[dev->devno] == 1))
+		dnxfer_sel = ATA_DNXFER_ANY;
+		if (tries[dev->devno] == 1)
+			dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
+		if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
 			tries[dev->devno] = 0;
 	}
 
 	if (!tries[dev->devno]) {
-		ata_down_xfermask_limit(dev, 1);
+		ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0);
 		ata_dev_disable(dev);
 	}
 

@@ -2267,7 +2270,7 @@ int ata_timing_compute(struct ata_device *adev, unsigned short speed,
 /**
  *	ata_down_xfermask_limit - adjust dev xfer masks downward
  *	@dev: Device to adjust xfer masks
- *	@force_pio0: Force PIO0
+ *	@sel: ATA_DNXFER_* selector
  *
  *	Adjust xfer masks of @dev downward.  Note that this function
  *	does not apply the change.  Invoking ata_set_mode() afterwards

@@ -2279,37 +2282,87 @@ int ata_timing_compute(struct ata_device *adev, unsigned short speed,
  *	RETURNS:
  *	0 on success, negative errno on failure
  */
-int ata_down_xfermask_limit(struct ata_device *dev, int force_pio0)
+int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel)
 {
-	unsigned long xfer_mask;
-	int highbit;
+	char buf[32];
+	unsigned int orig_mask, xfer_mask;
+	unsigned int pio_mask, mwdma_mask, udma_mask;
+	int quiet, highbit;
 
-	xfer_mask = ata_pack_xfermask(dev->pio_mask, dev->mwdma_mask,
-				      dev->udma_mask);
+	quiet = !!(sel & ATA_DNXFER_QUIET);
+	sel &= ~ATA_DNXFER_QUIET;
 
-	if (!xfer_mask)
-		goto fail;
-	/* don't gear down to MWDMA from UDMA, go directly to PIO */
-	if (xfer_mask & ATA_MASK_UDMA)
-		xfer_mask &= ~ATA_MASK_MWDMA;
+	xfer_mask = orig_mask = ata_pack_xfermask(dev->pio_mask,
+						  dev->mwdma_mask,
+						  dev->udma_mask);
+	ata_unpack_xfermask(xfer_mask, &pio_mask, &mwdma_mask, &udma_mask);
 
-	highbit = fls(xfer_mask) - 1;
-	xfer_mask &= ~(1 << highbit);
-	if (force_pio0)
-		xfer_mask &= 1 << ATA_SHIFT_PIO;
-	if (!xfer_mask)
-		goto fail;
+	switch (sel) {
+	case ATA_DNXFER_PIO:
+		highbit = fls(pio_mask) - 1;
+		pio_mask &= ~(1 << highbit);
+		break;
+
+	case ATA_DNXFER_DMA:
+		if (udma_mask) {
+			highbit = fls(udma_mask) - 1;
+			udma_mask &= ~(1 << highbit);
+			if (!udma_mask)
+				return -ENOENT;
+		} else if (mwdma_mask) {
+			highbit = fls(mwdma_mask) - 1;
+			mwdma_mask &= ~(1 << highbit);
+			if (!mwdma_mask)
+				return -ENOENT;
+		}
+		break;
+
+	case ATA_DNXFER_40C:
+		udma_mask &= ATA_UDMA_MASK_40C;
+		break;
+
+	case ATA_DNXFER_FORCE_PIO0:
+		pio_mask &= 1;
+	case ATA_DNXFER_FORCE_PIO:
+		mwdma_mask = 0;
+		udma_mask = 0;
+		break;
+
+	case ATA_DNXFER_ANY:
+		/* don't gear down to MWDMA from UDMA, go directly to PIO */
+		if (xfer_mask & ATA_MASK_UDMA)
+			xfer_mask &= ~ATA_MASK_MWDMA;
+
+		highbit = fls(xfer_mask) - 1;
+		xfer_mask &= ~(1 << highbit);
+		break;
+
+	default:
+		BUG();
+	}
+
+	xfer_mask &= ata_pack_xfermask(pio_mask, mwdma_mask, udma_mask);
+
+	if (!(xfer_mask & ATA_MASK_PIO) || xfer_mask == orig_mask)
+		return -ENOENT;
+
+	if (!quiet) {
+		if (xfer_mask & (ATA_MASK_MWDMA | ATA_MASK_UDMA))
+			snprintf(buf, sizeof(buf), "%s:%s",
+				 ata_mode_string(xfer_mask),
+				 ata_mode_string(xfer_mask & ATA_MASK_PIO));
+		else
+			snprintf(buf, sizeof(buf), "%s",
+				 ata_mode_string(xfer_mask));
+
+		ata_dev_printk(dev, KERN_WARNING,
+			       "limiting speed to %s\n", buf);
+	}
 
 	ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,
 			    &dev->udma_mask);
 
-	ata_dev_printk(dev, KERN_WARNING, "limiting speed to %s\n",
-		       ata_mode_string(xfer_mask));
-
 	return 0;
-
- fail:
-	return -EINVAL;
 }
 
 static int ata_dev_set_mode(struct ata_device *dev)

index 52c85af..7b61562 100644
@@ -1276,7 +1276,7 @@ static int ata_eh_speed_down(struct ata_device *dev, int is_io,
 		return ATA_EH_HARDRESET;
 
 	/* lower transfer mode */
-	if (ata_down_xfermask_limit(dev, 0) == 0)
+	if (ata_down_xfermask_limit(dev, ATA_DNXFER_ANY) == 0)
 		return ATA_EH_SOFTRESET;
 
 	ata_dev_printk(dev, KERN_ERR,

@@ -1965,6 +1965,7 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 	struct ata_eh_context *ehc = &ap->eh_context;
 	struct ata_device *dev;
 	int down_xfermask, i, rc;
+	int dnxfer_sel;
 
 	DPRINTK("ENTER\n");
 

@@ -2064,8 +2065,10 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 		sata_down_spd_limit(ap);
 	default:
 		ehc->tries[dev->devno]--;
-		if (down_xfermask &&
-		    ata_down_xfermask_limit(dev, ehc->tries[dev->devno] == 1))
+		dnxfer_sel = ATA_DNXFER_ANY;
+		if (ehc->tries[dev->devno] == 1)
+			dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
+		if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
 			ehc->tries[dev->devno] = 0;
 	}
 

index 06ccf23..36e08d2 100644
@@ -41,6 +41,16 @@ struct ata_scsi_args {
 enum {
 	/* flags for ata_dev_read_id() */
 	ATA_READID_POSTRESET	= (1 << 0), /* reading ID after reset */
+
+	/* selector for ata_down_xfermask_limit() */
+	ATA_DNXFER_PIO		= 0,	/* speed down PIO */
+	ATA_DNXFER_DMA		= 1,	/* speed down DMA */
+	ATA_DNXFER_40C		= 2,	/* apply 40c cable limit */
+	ATA_DNXFER_FORCE_PIO	= 3,	/* force PIO */
+	ATA_DNXFER_FORCE_PIO0	= 4,	/* force PIO0 */
+	ATA_DNXFER_ANY		= 5,	/* speed down any */
+
+	ATA_DNXFER_QUIET	= (1 << 31),
 };
 
 extern struct workqueue_struct *ata_aux_wq;

@@ -68,7 +78,7 @@ extern int ata_dev_revalidate(struct ata_device *dev, unsigned int flags);
 extern int ata_dev_configure(struct ata_device *dev);
 extern int sata_down_spd_limit(struct ata_port *ap);
 extern int sata_set_spd_needed(struct ata_port *ap);
-extern int ata_down_xfermask_limit(struct ata_device *dev, int force_pio0);
+extern int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel);
 extern int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev);
 extern void ata_sg_clean(struct ata_queued_cmd *qc);
 extern void ata_qc_free(struct ata_queued_cmd *qc);

index 1abfdba..3173862 100644
@@ -44,6 +44,12 @@
 
 #include "libata.h"
 
+enum {
+	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
+	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
+	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
+};
+
 static void __ata_port_freeze(struct ata_port *ap);
 static void ata_eh_finish(struct ata_port *ap);
 static void ata_eh_handle_port_suspend(struct ata_port *ap);

@@ -65,12 +71,9 @@ static void ata_ering_record(struct ata_ering *ering, int is_io,
 	ent->timestamp = get_jiffies_64();
 }
 
-static struct ata_ering_entry * ata_ering_top(struct ata_ering *ering)
+static void ata_ering_clear(struct ata_ering *ering)
 {
-	struct ata_ering_entry *ent = &ering->ring[ering->cursor];
-	if (!ent->err_mask)
-		return NULL;
-	return ent;
+	memset(ering, 0, sizeof(*ering));
 }
 
 static int ata_ering_map(struct ata_ering *ering,

@@ -1159,87 +1162,99 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
 	return action;
 }
 
-static int ata_eh_categorize_ering_entry(struct ata_ering_entry *ent)
+static int ata_eh_categorize_error(int is_io, unsigned int err_mask)
 {
-	if (ent->err_mask & (AC_ERR_ATA_BUS | AC_ERR_TIMEOUT))
+	if (err_mask & AC_ERR_ATA_BUS)
 		return 1;
 
-	if (ent->is_io) {
-		if (ent->err_mask & AC_ERR_HSM)
-			return 1;
-		if ((ent->err_mask &
-		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
+	if (err_mask & AC_ERR_TIMEOUT)
+		return 2;
+
+	if (is_io) {
+		if (err_mask & AC_ERR_HSM)
 			return 2;
+		if ((err_mask &
+		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
+			return 3;
 	}
 
 	return 0;
 }
 
-struct speed_down_needed_arg {
+struct speed_down_verdict_arg {
 	u64 since;
-	int nr_errors[3];
+	int nr_errors[4];
 };
 
-static int speed_down_needed_cb(struct ata_ering_entry *ent, void *void_arg)
+static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
 {
-	struct speed_down_needed_arg *arg = void_arg;
+	struct speed_down_verdict_arg *arg = void_arg;
+	int cat = ata_eh_categorize_error(ent->is_io, ent->err_mask);
 
 	if (ent->timestamp < arg->since)
 		return -1;
 
-	arg->nr_errors[ata_eh_categorize_ering_entry(ent)]++;
+	arg->nr_errors[cat]++;
 	return 0;
 }
 
 /**
- *	ata_eh_speed_down_needed - Determine wheter speed down is necessary
+ *	ata_eh_speed_down_verdict - Determine speed down verdict
  *	@dev: Device of interest
  *
  *	This function examines error ring of @dev and determines
- *	whether speed down is necessary.  Speed down is necessary if
- *	there have been more than 3 of Cat-1 errors or 10 of Cat-2
- *	errors during last 15 minutes.
+ *	whether NCQ needs to be turned off, transfer speed should be
+ *	stepped down, or falling back to PIO is necessary.
+ *
+ *	Cat-1 is ATA_BUS error for any command.
  *
- *	Cat-1 errors are ATA_BUS, TIMEOUT for any command and HSM
- *	violation for known supported commands.
+ *	Cat-2 is TIMEOUT for any command or HSM violation for known
+ *	supported commands.
  *
- *	Cat-2 errors are unclassified DEV error for known supported
+ *	Cat-3 is is unclassified DEV error for known supported
  *	command.
  *
+ *	NCQ needs to be turned off if there have been more than 3
+ *	Cat-2 + Cat-3 errors during last 10 minutes.
+ *
+ *	Speed down is necessary if there have been more than 3 Cat-1 +
+ *	Cat-2 errors or 10 Cat-3 errors during last 10 minutes.
+ *
+ *	Falling back to PIO mode is necessary if there have been more
+ *	than 10 Cat-1 + Cat-2 + Cat-3 errors during last 5 minutes.
+ *
  *	LOCKING:
  *	Inherited from caller.
  *
  *	RETURNS:
- *	1 if speed down is necessary, 0 otherwise
+ *	OR of ATA_EH_SPDN_* flags.
  */
-static int ata_eh_speed_down_needed(struct ata_device *dev)
+static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 {
-	const u64 interval = 15LLU * 60 * HZ;
-	static const int err_limits[3] = { -1, 3, 10 };
-	struct speed_down_needed_arg arg;
-	struct ata_ering_entry *ent;
-	int err_cat;
-	u64 j64;
+	const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
+	u64 j64 = get_jiffies_64();
+	struct speed_down_verdict_arg arg;
+	unsigned int verdict = 0;
 
-	ent = ata_ering_top(&dev->ering);
-	if (!ent)
-		return 0;
+	/* scan past 10 mins of error history */
+	memset(&arg, 0, sizeof(arg));
+	arg.since = j64 - min(j64, j10mins);
+	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
-	err_cat = ata_eh_categorize_ering_entry(ent);
-	if (err_cat == 0)
-		return 0;
+	if (arg.nr_errors[2] + arg.nr_errors[3] > 3)
+		verdict |= ATA_EH_SPDN_NCQ_OFF;
+	if (arg.nr_errors[1] + arg.nr_errors[2] > 3 || arg.nr_errors[3] > 10)
+		verdict |= ATA_EH_SPDN_SPEED_DOWN;
 
+	/* scan past 3 mins of error history */
 	memset(&arg, 0, sizeof(arg));
+	arg.since = j64 - min(j64, j5mins);
+	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
-	j64 = get_jiffies_64();
-	if (j64 >= interval)
-		arg.since = j64 - interval;
-	else
-		arg.since = 0;
-
-	ata_ering_map(&dev->ering, speed_down_needed_cb, &arg);
+	if (arg.nr_errors[1] + arg.nr_errors[2] + arg.nr_errors[3] > 10)
+		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
 
-	return arg.nr_errors[err_cat] > err_limits[err_cat];
+	return verdict;
 }
 
 /**

@@ -1257,31 +1272,80 @@ static int ata_eh_speed_down_needed(struct ata_device *dev)
  *	Kernel thread context (may sleep).
  *
  *	RETURNS:
- *	0 on success, -errno otherwise
+ *	Determined recovery action.
  */
-static int ata_eh_speed_down(struct ata_device *dev, int is_io,
-			     unsigned int err_mask)
+static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io,
+				      unsigned int err_mask)
 {
-	if (!err_mask)
+	unsigned int verdict;
+	unsigned int action = 0;
+
+	/* don't bother if Cat-0 error */
+	if (ata_eh_categorize_error(is_io, err_mask) == 0)
 		return 0;
 
 	/* record error and determine whether speed down is necessary */
 	ata_ering_record(&dev->ering, is_io, err_mask);
+	verdict = ata_eh_speed_down_verdict(dev);
 
-	if (!ata_eh_speed_down_needed(dev))
-		return 0;
+	/* turn off NCQ? */
+	if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
+	    (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
+			   ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
+		dev->flags |= ATA_DFLAG_NCQ_OFF;
+		ata_dev_printk(dev, KERN_WARNING,
+			       "NCQ disabled due to excessive errors\n");
+		goto done;
+	}
+
+	/* speed down? */
+	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
+		/* speed down SATA link speed if possible */
+		if (sata_down_spd_limit(dev->ap) == 0) {
+			action |= ATA_EH_HARDRESET;
+			goto done;
+		}
 
-	/* speed down SATA link speed if possible */
-	if (sata_down_spd_limit(dev->ap) == 0)
-		return ATA_EH_HARDRESET;
+		/* lower transfer mode */
+		if (dev->spdn_cnt < 2) {
+			static const int dma_dnxfer_sel[] =
+				{ ATA_DNXFER_DMA, ATA_DNXFER_40C };
+			static const int pio_dnxfer_sel[] =
+				{ ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
+			int sel;
 
-	/* lower transfer mode */
-	if (ata_down_xfermask_limit(dev, ATA_DNXFER_ANY) == 0)
-		return ATA_EH_SOFTRESET;
+			if (dev->xfer_shift != ATA_SHIFT_PIO)
+				sel = dma_dnxfer_sel[dev->spdn_cnt];
+			else
+				sel = pio_dnxfer_sel[dev->spdn_cnt];
+
+			dev->spdn_cnt++;
+
+			if (ata_down_xfermask_limit(dev, sel) == 0) {
+				action |= ATA_EH_SOFTRESET;
+				goto done;
+			}
+		}
+	}
+
+	/* Fall back to PIO?  Slowing down to PIO is meaningless for
+	 * SATA.  Consider it only for PATA.
+	 */
+	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
+	    (dev->ap->cbl != ATA_CBL_SATA) &&
+	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
+		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
+			dev->spdn_cnt = 0;
+			action |= ATA_EH_SOFTRESET;
+			goto done;
+		}
+	}
 
-	ata_dev_printk(dev, KERN_ERR,
-		       "speed down requested but no transfer mode left\n");
 	return 0;
+ done:
+	/* device has been slowed down, blow error history */
+	ata_ering_clear(&dev->ering);
+	return action;
 }
 
 /**

index 4c3ed59..1b3963f 100644
@@ -495,6 +495,7 @@ struct ata_device {
 
 	/* error history */
 	struct ata_ering	ering;
+	int			spdn_cnt;
 	unsigned int		horkage;	/* List of broken features */
 };
 

index 417394b..cbd4bf1 100644
@@ -596,6 +596,8 @@ void ata_dev_disable(struct ata_device *dev)
 {
 	if (ata_dev_enabled(dev) && ata_msg_drv(dev->ap)) {
 		ata_dev_printk(dev, KERN_WARNING, "disabled\n");
+		ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 |
+					     ATA_DNXFER_QUIET);
 		dev->class++;
 	}
 }

@@ -1745,9 +1747,8 @@ int ata_bus_probe(struct ata_port *ap)
 {
 	unsigned int classes[ATA_MAX_DEVICES];
 	int tries[ATA_MAX_DEVICES];
-	int i, rc, down_xfermask;
+	int i, rc;
 	struct ata_device *dev;
-	int dnxfer_sel;
 
 	ata_port_probe(ap);
 

@@ -1755,8 +1756,6 @@ int ata_bus_probe(struct ata_port *ap)
 		tries[i] = ATA_PROBE_MAX_TRIES;
 
  retry:
-	down_xfermask = 0;
-
 	/* reset and determine device classes */
 	ap->ops->phy_reset(ap);
 

@@ -1804,10 +1803,8 @@ int ata_bus_probe(struct ata_port *ap)
 
 	/* configure transfer mode */
 	rc = ata_set_mode(ap, &dev);
-	if (rc) {
-		down_xfermask = 1;
+	if (rc)
 		goto fail;
-	}
 
 	for (i = 0; i < ATA_MAX_DEVICES; i++)
 		if (ata_dev_enabled(&ap->device[i]))

@@ -1819,27 +1816,29 @@ int ata_bus_probe(struct ata_port *ap)
 	return -ENODEV;
 
  fail:
+	tries[dev->devno]--;
+
 	switch (rc) {
 	case -EINVAL:
-	case -ENODEV:
+		/* eeek, something went very wrong, give up */
 		tries[dev->devno] = 0;
 		break;
+
+	case -ENODEV:
+		/* give it just one more chance */
+		tries[dev->devno] = min(tries[dev->devno], 1);
 	case -EIO:
-		sata_down_spd_limit(ap);
-		/* fall through */
-	default:
-		tries[dev->devno]--;
-		dnxfer_sel = ATA_DNXFER_ANY;
-		if (tries[dev->devno] == 1)
-			dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
-		if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
-			tries[dev->devno] = 0;
+		if (tries[dev->devno] == 1) {
+			/* This is the last chance, better to slow
+			 * down than lose it.
+			 */
+			sata_down_spd_limit(ap);
+			ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
+		}
 	}
 
-	if (!tries[dev->devno]) {
-		ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0);
+	if (!tries[dev->devno])
 		ata_dev_disable(dev);
-	}
 
 	goto retry;
 }

index 7b61562..1abfdba 100644
@@ -1964,8 +1964,7 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 {
 	struct ata_eh_context *ehc = &ap->eh_context;
 	struct ata_device *dev;
-	int down_xfermask, i, rc;
-	int dnxfer_sel;
+	int i, rc;
 
 	DPRINTK("ENTER\n");
 

@@ -1994,7 +1993,6 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 	}
 
  retry:
-	down_xfermask = 0;
 	rc = 0;
 
 	/* if UNLOADING, finish immediately */

@@ -2039,10 +2037,8 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 	/* configure transfer mode if necessary */
 	if (ehc->i.flags & ATA_EHI_SETMODE) {
 		rc = ata_set_mode(ap, &dev);
-		if (rc) {
-			down_xfermask = 1;
+		if (rc)
 			goto dev_fail;
-		}
 		ehc->i.flags &= ~ATA_EHI_SETMODE;
 	}
 

@@ -2054,22 +2050,27 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 	goto out;
 
  dev_fail:
+	ehc->tries[dev->devno]--;
+
 	switch (rc) {
-	case -ENODEV:
-		/* device missing, schedule probing */
-		ehc->i.probe_mask |= (1 << dev->devno);
 	case -EINVAL:
+		/* eeek, something went very wrong, give up */
 		ehc->tries[dev->devno] = 0;
 		break;
+
+	case -ENODEV:
+		/* device missing or wrong IDENTIFY data, schedule probing */
+		ehc->i.probe_mask |= (1 << dev->devno);
+		/* give it just one more chance */
+		ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
 	case -EIO:
-		sata_down_spd_limit(ap);
-	default:
-		ehc->tries[dev->devno]--;
-		dnxfer_sel = ATA_DNXFER_ANY;
-		if (ehc->tries[dev->devno] == 1)
-			dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
-		if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
-			ehc->tries[dev->devno] = 0;
+		if (ehc->tries[dev->devno] == 1) {
+			/* This is the last chance, better to slow
+			 * down than lose it.
+			 */
+			sata_down_spd_limit(ap);
+			ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
+		}
 	}
 
 	if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {

index 8f1d753..1d8d377 100644
@@ -199,7 +199,6 @@ struct ahci_port_priv {
 	void			*rx_fis;
 	dma_addr_t		rx_fis_dma;
 	/* for NCQ spurious interrupt analysis */
-	int			ncq_saw_spurious_sdb_cnt;
 	unsigned int		ncq_saw_d2h:1;
 	unsigned int		ncq_saw_dmas:1;
 };

@@ -1157,23 +1156,24 @@ static void ahci_host_intr(struct ata_port *ap)
 		known_irq = 1;
 	}
 
-	if (status & PORT_IRQ_SDB_FIS &&
-		   pp->ncq_saw_spurious_sdb_cnt < 10) {
+	if (status & PORT_IRQ_SDB_FIS) {
 		/* SDB FIS containing spurious completions might be
-		 * dangerous, we need to know more about them.  Print
-		 * more of it.
+		 * dangerous, whine and fail commands with HSM
+		 * violation.  EH will turn off NCQ after several such
+		 * failures.
 		 */
 		const u32 *f = pp->rx_fis + RX_FIS_SDB;
 
-		ata_port_printk(ap, KERN_INFO, "Spurious SDB FIS during NCQ "
-				"issue=0x%x SAct=0x%x FIS=%08x:%08x%s\n",
-				readl(port_mmio + PORT_CMD_ISSUE),
-				readl(port_mmio + PORT_SCR_ACT),
-				le32_to_cpu(f[0]), le32_to_cpu(f[1]),
-				pp->ncq_saw_spurious_sdb_cnt < 10 ?
-				"" : ", shutting up");
+		ata_ehi_push_desc(ehi, "spurious completion during NCQ "
+				  "issue=0x%x SAct=0x%x FIS=%08x:%08x",
+				  readl(port_mmio + PORT_CMD_ISSUE),
+				  readl(port_mmio + PORT_SCR_ACT),
+				  le32_to_cpu(f[0]), le32_to_cpu(f[1]));
+
+		ehi->err_mask |= AC_ERR_HSM;
+		ehi->action |= ATA_EH_SOFTRESET;
+		ata_port_freeze(ap);
 
-		pp->ncq_saw_spurious_sdb_cnt++;
 		known_irq = 1;
 	}
 

index cbd4bf1..651ab4b 100644
@@ -2327,15 +2327,6 @@ int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel)
 		udma_mask = 0;
 		break;
 
-	case ATA_DNXFER_ANY:
-		/* don't gear down to MWDMA from UDMA, go directly to PIO */
-		if (xfer_mask & ATA_MASK_UDMA)
-			xfer_mask &= ~ATA_MASK_MWDMA;
-
-		highbit = fls(xfer_mask) - 1;
-		xfer_mask &= ~(1 << highbit);
-		break;
-
 	default:
 		BUG();
 	}

index 36e08d2..6fc6260 100644
@@ -48,7 +48,6 @@ enum {
 	ATA_DNXFER_40C		= 2,	/* apply 40c cable limit */
 	ATA_DNXFER_FORCE_PIO	= 3,	/* force PIO */
 	ATA_DNXFER_FORCE_PIO0	= 4,	/* force PIO0 */
-	ATA_DNXFER_ANY		= 5,	/* speed down any */
 
 	ATA_DNXFER_QUIET	= (1 << 31),
 };

index 6a3543e..334f54c 100644
@@ -198,7 +198,6 @@ struct ahci_port_priv {
 	void			*rx_fis;
 	dma_addr_t		rx_fis_dma;
 	/* for NCQ spurious interrupt analysis */
-	int			ncq_saw_spurious_sdb_cnt;
 	unsigned int		ncq_saw_d2h:1;
 	unsigned int		ncq_saw_dmas:1;
 };

@@ -1160,23 +1159,24 @@ static void ahci_host_intr(struct ata_port *ap)
 		known_irq = 1;
 	}
 
-	if (status & PORT_IRQ_SDB_FIS &&
-		   pp->ncq_saw_spurious_sdb_cnt < 10) {
+	if (status & PORT_IRQ_SDB_FIS) {
 		/* SDB FIS containing spurious completions might be
-		 * dangerous, we need to know more about them.  Print
-		 * more of it.
-		 */
+		 * dangerous, whine and fail commands with HSM
+		 * violation.  EH will turn off NCQ after several such
+		 * failures.
+  		 */
 		const __le32 *f = pp->rx_fis + RX_FIS_SDB;
 
-		ata_port_printk(ap, KERN_INFO, "Spurious SDB FIS during NCQ "
-				"issue=0x%x SAct=0x%x FIS=%08x:%08x%s\n",
-				readl(port_mmio + PORT_CMD_ISSUE),
-				readl(port_mmio + PORT_SCR_ACT),
-				le32_to_cpu(f[0]), le32_to_cpu(f[1]),
-				pp->ncq_saw_spurious_sdb_cnt < 10 ?
-				"" : ", shutting up");
+		ata_ehi_push_desc(ehi, "spurious completion during NCQ "
+				  "issue=0x%x SAct=0x%x FIS=%08x:%08x",
+				  readl(port_mmio + PORT_CMD_ISSUE),
+				  readl(port_mmio + PORT_SCR_ACT),
+				  le32_to_cpu(f[0]), le32_to_cpu(f[1]));
+
+		ehi->err_mask |= AC_ERR_HSM;
+		ehi->action |= ATA_EH_SOFTRESET;
+		ata_port_freeze(ap);
 
-		pp->ncq_saw_spurious_sdb_cnt++;
 		known_irq = 1;
 	}