libata: update EH speed down logic, take #2

index 1e27785..65274d5 100644
@@ -141,10 +141,10 @@ enum {
 	ATA_DFLAG_NCQ_OFF	= (1 << 13), /* device limited to non-NCQ mode */
 	ATA_DFLAG_SPUNDOWN	= (1 << 14), /* XXX: for spindown_compat */
 	ATA_DFLAG_SLEEPING	= (1 << 15), /* device is sleeping */
-	ATA_DFLAG_INIT_MASK	= (1 << 16) - 1,
+	ATA_DFLAG_INIT_MASK	= (1 << 24) - 1,
 
-	ATA_DFLAG_DETACH	= (1 << 16),
-	ATA_DFLAG_DETACHED	= (1 << 17),
+	ATA_DFLAG_DETACH	= (1 << 24),
+	ATA_DFLAG_DETACHED	= (1 << 25),
 
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */

index 61535e7..2318531 100644
@@ -323,6 +323,27 @@ enum ata_tf_protocols {
 	ATA_PROT_ATAPI_DMA,	/* packet command with special DMA sauce */
 };
 
+static inline int ata_is_nodata(u8 prot)
+{
+	return prot == ATA_PROT_NODATA || prot == ATA_PROT_ATAPI_NODATA;
+}
+
+static inline int ata_is_pio_data(u8 prot)
+{
+	return prot == ATA_PROT_PIO || prot == ATA_PROT_ATAPI;
+}
+
+static inline int ata_is_dma_data(u8 prot)
+{
+	return prot == ATA_PROT_DMA || prot == ATA_PROT_NCQ ||
+		prot == ATA_PROT_ATAPI_DMA;
+}
+
+static inline int ata_is_data(u8 prot)
+{
+	return ata_is_pio_data(prot) || ata_is_dma_data(prot);
+}
+
 enum ata_ioctls {
 	ATA_IOC_GET_IO32	= 0x309,
 	ATA_IOC_SET_IO32	= 0x324,

index ed8813b..a37be1e 100644
@@ -2438,6 +2438,22 @@ static int ata_eh_skip_recovery(struct ata_link *link)
 	return 1;
 }
 
+static int ata_eh_schedule_probe(struct ata_device *dev)
+{
+	struct ata_eh_context *ehc = &dev->link->eh_context;
+
+	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
+	    (ehc->did_probe_mask & (1 << dev->devno)))
+		return 0;
+
+	ata_eh_detach_dev(dev);
+	ata_dev_init(dev);
+	ehc->did_probe_mask |= (1 << dev->devno);
+	ehc->i.action |= ATA_EH_SOFTRESET;
+
+	return 1;
+}
+
 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
 {
 	struct ata_eh_context *ehc = &dev->link->eh_context;

@@ -2469,16 +2485,9 @@ static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
 		if (ata_link_offline(dev->link))
 			ata_eh_detach_dev(dev);
 
-		/* probe if requested */
-		if ((ehc->i.probe_mask & (1 << dev->devno)) &&
-		    !(ehc->did_probe_mask & (1 << dev->devno))) {
-			ata_eh_detach_dev(dev);
-			ata_dev_init(dev);
-
+		/* schedule probe if necessary */
+		if (ata_eh_schedule_probe(dev))
 			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
-			ehc->did_probe_mask |= (1 << dev->devno);
-			ehc->i.action |= ATA_EH_SOFTRESET;
-		}
 
 		return 1;
 	} else {

@@ -2555,14 +2564,8 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 			if (dev->flags & ATA_DFLAG_DETACH)
 				ata_eh_detach_dev(dev);
 
-			if (!ata_dev_enabled(dev) &&
-			    ((ehc->i.probe_mask & (1 << dev->devno)) &&
-			     !(ehc->did_probe_mask & (1 << dev->devno)))) {
-				ata_eh_detach_dev(dev);
-				ata_dev_init(dev);
-				ehc->did_probe_mask |= (1 << dev->devno);
-				ehc->i.action |= ATA_EH_SOFTRESET;
-			}
+			/* schedule probe if necessary */
+			ata_eh_schedule_probe(dev);
 		}
 	}
 

Index: work/drivers/ata/libata-eh.c
===================================================================
@@ -2438,6 +2438,22 @@ static int ata_eh_skip_recovery(struct a
 	return 1;
 }
 
+static int ata_eh_schedule_probe(struct ata_device *dev)
+{
+	struct ata_eh_context *ehc = &dev->link->eh_context;
+
+	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
+	    (ehc->did_probe_mask & (1 << dev->devno)))
+		return 0;
+
+	ata_eh_detach_dev(dev);
+	ata_dev_init(dev);
+	ehc->did_probe_mask |= (1 << dev->devno);
+	ehc->i.action |= ATA_EH_SOFTRESET;
+
+	return 1;
+}
+
 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
 {
 	struct ata_eh_context *ehc = &dev->link->eh_context;

@@ -2469,16 +2485,9 @@ static int ata_eh_handle_dev_fail(struct
 		if (ata_link_offline(dev->link))
 			ata_eh_detach_dev(dev);
 
-		/* probe if requested */
-		if ((ehc->i.probe_mask & (1 << dev->devno)) &&
-		    !(ehc->did_probe_mask & (1 << dev->devno))) {
-			ata_eh_detach_dev(dev);
-			ata_dev_init(dev);
-
+		/* schedule probe if necessary */
+		if (ata_eh_schedule_probe(dev))
 			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
-			ehc->did_probe_mask |= (1 << dev->devno);
-			ehc->i.action |= ATA_EH_SOFTRESET;
-		}
 
 		return 1;
 	} else {

@@ -2555,14 +2564,9 @@ int ata_eh_recover(struct ata_port *ap, 
 			if (dev->flags & ATA_DFLAG_DETACH)
 				ata_eh_detach_dev(dev);
 
-			if (!ata_dev_enabled(dev) &&
-			    ((ehc->i.probe_mask & (1 << dev->devno)) &&
-			     !(ehc->did_probe_mask & (1 << dev->devno)))) {
-				ata_eh_detach_dev(dev);
-				ata_dev_init(dev);
-				ehc->did_probe_mask |= (1 << dev->devno);
-				ehc->i.action |= ATA_EH_SOFTRESET;
-			}
+			/* schedule probe if necessary */
+			if (!ata_dev_enabled(dev))
+				ata_eh_schedule_probe(dev);
 		}
 	}
 

index 164c7d9..0f02a07 100644
@@ -3234,31 +3234,6 @@ int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 }
 
 /**
- *	ata_set_mode - Program timings and issue SET FEATURES - XFER
- *	@link: link on which timings will be programmed
- *	@r_failed_dev: out paramter for failed device
- *
- *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
- *	ata_set_mode() fails, pointer to the failing device is
- *	returned in @r_failed_dev.
- *
- *	LOCKING:
- *	PCI/etc. bus probe sem.
- *
- *	RETURNS:
- *	0 on success, negative errno otherwise
- */
-int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
-{
-	struct ata_port *ap = link->ap;
-
-	/* has private set_mode? */
-	if (ap->ops->set_mode)
-		return ap->ops->set_mode(link, r_failed_dev);
-	return ata_do_set_mode(link, r_failed_dev);
-}
-
-/**
  *	ata_tf_to_host - issue ATA taskfile to host controller
  *	@ap: port to which command is being issued
  *	@tf: ATA taskfile register set

index a37be1e..ae03201 100644
@@ -2392,6 +2392,31 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
 	return rc;
 }
 
+/**
+ *	ata_set_mode - Program timings and issue SET FEATURES - XFER
+ *	@link: link on which timings will be programmed
+ *	@r_failed_dev: out paramter for failed device
+ *
+ *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
+ *	ata_set_mode() fails, pointer to the failing device is
+ *	returned in @r_failed_dev.
+ *
+ *	LOCKING:
+ *	PCI/etc. bus probe sem.
+ *
+ *	RETURNS:
+ *	0 on success, negative errno otherwise
+ */
+int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
+{
+	struct ata_port *ap = link->ap;
+
+	/* has private set_mode? */
+	if (ap->ops->set_mode)
+		return ap->ops->set_mode(link, r_failed_dev);
+	return ata_do_set_mode(link, r_failed_dev);
+}
+
 static int ata_link_nr_enabled(struct ata_link *link)
 {
 	struct ata_device *dev;

index 0e6cf3a..9e9a2a9 100644
@@ -85,7 +85,6 @@ extern int ata_dev_configure(struct ata_device *dev);
 extern int sata_down_spd_limit(struct ata_link *link);
 extern int sata_set_spd_needed(struct ata_link *link);
 extern int ata_down_xfermask_limit(struct ata_device *dev, unsigned int sel);
-extern int ata_set_mode(struct ata_link *link, 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);
 extern void ata_qc_issue(struct ata_queued_cmd *qc);

@@ -179,6 +178,7 @@ extern void ata_eh_report(struct ata_port *ap);
 extern int ata_eh_reset(struct ata_link *link, int classify,
 			ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
 			ata_reset_fn_t hardreset, ata_postreset_fn_t postreset);
+extern int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev);
 extern int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 			  ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
 			  ata_postreset_fn_t postreset,

index ae03201..7f505f1 100644
@@ -46,9 +46,20 @@
 #include "libata.h"
 
 enum {
+	/* speed down verdicts */
 	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
 	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
 	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
+
+	/* error flags */
+	ATA_EFLAG_IS_IO			= (1 << 0),
+
+	/* error categories */
+	ATA_ECAT_NONE			= 0,
+	ATA_ECAT_ATA_BUS		= 1,
+	ATA_ECAT_TOUT_HSM		= 2,
+	ATA_ECAT_UNK_DEV		= 3,
+	ATA_ECAT_NR			= 4,
 };
 
 /* Waiting in ->prereset can never be reliable.  It's sometimes nice

@@ -218,7 +229,7 @@ void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
 
 #endif /* CONFIG_PCI */
 
-static void ata_ering_record(struct ata_ering *ering, int is_io,
+static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
 			     unsigned int err_mask)
 {
 	struct ata_ering_entry *ent;

@@ -229,7 +240,7 @@ static void ata_ering_record(struct ata_ering *ering, int is_io,
 	ering->cursor %= ATA_ERING_SIZE;
 
 	ent = &ering->ring[ering->cursor];
-	ent->is_io = is_io;
+	ent->eflags = eflags;
 	ent->err_mask = err_mask;
 	ent->timestamp = get_jiffies_64();
 }

@@ -1546,20 +1557,20 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
 	return action;
 }
 
-static int ata_eh_categorize_error(int is_io, unsigned int err_mask)
+static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask)
 {
 	if (err_mask & AC_ERR_ATA_BUS)
-		return 1;
+		return ATA_ECAT_ATA_BUS;
 
 	if (err_mask & AC_ERR_TIMEOUT)
-		return 2;
+		return ATA_ECAT_TOUT_HSM;
 
-	if (is_io) {
+	if (eflags & ATA_EFLAG_IS_IO) {
 		if (err_mask & AC_ERR_HSM)
-			return 2;
+			return ATA_ECAT_TOUT_HSM;
 		if ((err_mask &
 		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
-			return 3;
+			return ATA_ECAT_UNK_DEV;
 	}
 
 	return 0;

@@ -1567,13 +1578,13 @@ static int ata_eh_categorize_error(int is_io, unsigned int err_mask)
 
 struct speed_down_verdict_arg {
 	u64 since;
-	int nr_errors[4];
+	int nr_errors[ATA_ECAT_NR];
 };
 
 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
 {
 	struct speed_down_verdict_arg *arg = void_arg;
-	int cat = ata_eh_categorize_error(ent->is_io, ent->err_mask);
+	int cat = ata_eh_categorize_error(ent->eflags, ent->err_mask);
 
 	if (ent->timestamp < arg->since)
 		return -1;

@@ -1590,22 +1601,33 @@ static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
  *	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.
+ *	ECAT_ATA_BUS	: ATA_BUS error for any command
+ *
+ *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for
+ *			  IO commands
+ *
+ *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
+ *
+ *	Verdicts are
  *
- *	Cat-2 is TIMEOUT for any command or HSM violation for known
- *	supported commands.
+ *	NCQ_OFF		: Turn off NCQ.
  *
- *	Cat-3 is is unclassified DEV error for known supported
- *	command.
+ *	SPEED_DOWN	: Speed down transfer speed but don't fall back
+ *			  to PIO.
  *
- *	NCQ needs to be turned off if there have been more than 3
- *	Cat-2 + Cat-3 errors during last 10 minutes.
+ *	FALLBACK_TO_PIO	: Fall back to PIO.
  *
- *	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.
+ *	Even if multiple verdicts are returned, only one action is
+ *	taken per error.  ering is cleared after an action is taken.
  *
- *	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.
+ *	1. If more than 10 ATA_BUS, TOUT_HSM or UNK_DEV errors
+ *	   ocurred during last 5 mins, FALLBACK_TO_PIO
+ *
+ *	2. If more than 3 TOUT_HSM or UNK_DEV errors occurred
+ *	   during last 10 mins, NCQ_OFF.
+ *
+ *	3. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 10
+ *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
  *
  *	LOCKING:
  *	Inherited from caller.

@@ -1620,23 +1642,29 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 	struct speed_down_verdict_arg arg;
 	unsigned int verdict = 0;
 
-	/* scan past 10 mins of error history */
+	/* scan past 5 mins of error history */
 	memset(&arg, 0, sizeof(arg));
-	arg.since = j64 - min(j64, j10mins);
+	arg.since = j64 - min(j64, j5mins);
 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
-	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;
+	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
+	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
+	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 10)
+		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
 
-	/* scan past 3 mins of error history */
+	/* scan past 10 mins of error history */
 	memset(&arg, 0, sizeof(arg));
-	arg.since = j64 - min(j64, j5mins);
+	arg.since = j64 - min(j64, j10mins);
 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
-	if (arg.nr_errors[1] + arg.nr_errors[2] + arg.nr_errors[3] > 10)
-		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
+	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
+	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
+		verdict |= ATA_EH_SPDN_NCQ_OFF;
+
+	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
+	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
+	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 10)
+		verdict |= ATA_EH_SPDN_SPEED_DOWN;
 
 	return verdict;
 }

@@ -1644,7 +1672,7 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 /**
  *	ata_eh_speed_down - record error and speed down if necessary
  *	@dev: Failed device
- *	@is_io: Did the device fail during normal IO?
+ *	@eflags: mask of ATA_EFLAG_* flags
  *	@err_mask: err_mask of the error
  *
  *	Record error and examine error history to determine whether

@@ -1658,18 +1686,19 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
  *	RETURNS:
  *	Determined recovery action.
  */
-static unsigned 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,
+				unsigned int eflags, unsigned int err_mask)
 {
+	struct ata_link *link = dev->link;
 	unsigned int verdict;
 	unsigned int action = 0;
 
 	/* don't bother if Cat-0 error */
-	if (ata_eh_categorize_error(is_io, err_mask) == 0)
+	if (ata_eh_categorize_error(eflags, err_mask) == 0)
 		return 0;
 
 	/* record error and determine whether speed down is necessary */
-	ata_ering_record(&dev->ering, is_io, err_mask);
+	ata_ering_record(&dev->ering, eflags, err_mask);
 	verdict = ata_eh_speed_down_verdict(dev);
 
 	/* turn off NCQ? */

@@ -1685,7 +1714,7 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io,
 	/* speed down? */
 	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
 		/* speed down SATA link speed if possible */
-		if (sata_down_spd_limit(dev->link) == 0) {
+		if (sata_down_spd_limit(link) == 0) {
 			action |= ATA_EH_HARDRESET;
 			goto done;
 		}

@@ -1716,7 +1745,7 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io,
 	 * SATA.  Consider it only for PATA.
 	 */
 	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
-	    (dev->link->ap->cbl != ATA_CBL_SATA) &&
+	    (link->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;

@@ -1748,8 +1777,8 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 	struct ata_port *ap = link->ap;
 	struct ata_eh_context *ehc = &link->eh_context;
 	struct ata_device *dev;
-	unsigned int all_err_mask = 0;
-	int tag, is_io = 0;
+	unsigned int all_err_mask = 0, eflags = 0;
+	int tag;
 	u32 serror;
 	int rc;
 

@@ -1808,15 +1837,15 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 		ehc->i.dev = qc->dev;
 		all_err_mask |= qc->err_mask;
 		if (qc->flags & ATA_QCFLAG_IO)
-			is_io = 1;
+			eflags |= ATA_EFLAG_IS_IO;
 	}
 
 	/* enforce default EH actions */
 	if (ap->pflags & ATA_PFLAG_FROZEN ||
 	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
 		ehc->i.action |= ATA_EH_SOFTRESET;
-	else if ((is_io && all_err_mask) ||
-		 (!is_io && (all_err_mask & ~AC_ERR_DEV)))
+	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
+		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
 		ehc->i.action |= ATA_EH_REVALIDATE;
 
 	/* If we have offending qcs and the associated failed device,

@@ -1835,7 +1864,7 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 		dev = link->device;
 
 	if (dev)
-		ehc->i.action |= ata_eh_speed_down(dev, is_io, all_err_mask);
+		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
 
 	DPRINTK("EXIT\n");
 }

index 65274d5..4abfb3c 100644
@@ -478,7 +478,7 @@ struct ata_port_stats {
 };
 
 struct ata_ering_entry {
-	int			is_io;
+	unsigned int		eflags;
 	unsigned int		err_mask;
 	u64			timestamp;
 };

index 7f505f1..cf2afb0 100644
@@ -1620,13 +1620,13 @@ static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
  *	Even if multiple verdicts are returned, only one action is
  *	taken per error.  ering is cleared after an action is taken.
  *
- *	1. If more than 10 ATA_BUS, TOUT_HSM or UNK_DEV errors
+ *	1. If more than 6 ATA_BUS, TOUT_HSM or UNK_DEV errors
  *	   ocurred during last 5 mins, FALLBACK_TO_PIO
  *
  *	2. If more than 3 TOUT_HSM or UNK_DEV errors occurred
  *	   during last 10 mins, NCQ_OFF.
  *
- *	3. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 10
+ *	3. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
  *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
  *
  *	LOCKING:

@@ -1649,7 +1649,7 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 
 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
-	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 10)
+	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
 		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
 
 	/* scan past 10 mins of error history */

@@ -1663,7 +1663,7 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 
 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
-	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 10)
+	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
 		verdict |= ATA_EH_SPDN_SPEED_DOWN;
 
 	return verdict;

@@ -1742,10 +1742,10 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev,
 	}
 
 	/* Fall back to PIO?  Slowing down to PIO is meaningless for
-	 * SATA.  Consider it only for PATA.
+	 * SATA ATA devices.  Consider it only for PATA and SATAPI.
 	 */
 	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
-	    (link->ap->cbl != ATA_CBL_SATA) &&
+	    (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
 	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
 		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
 			dev->spdn_cnt = 0;

index 0f02a07..47f0a30 100644
@@ -5777,6 +5777,23 @@ static void fill_result_tf(struct ata_queued_cmd *qc)
 	ap->ops->tf_read(ap, &qc->result_tf);
 }
 
+static void ata_verify_xfer(struct ata_queued_cmd *qc)
+{
+	struct ata_device *dev = qc->dev;
+
+	if (ata_tag_internal(qc->tag))
+		return;
+
+	if (ata_is_nodata(qc->tf.protocol))
+		return;
+
+	if ((dev->mwdma_mask || dev->udma_mask) &&
+	    ata_is_pio_data(qc->tf.protocol))
+		return;
+
+	dev->flags &= ~ATA_DFLAG_DUBIOUS_XFER;
+}
+
 /**
  *	ata_qc_complete - Complete an active ATA command
  *	@qc: Command to complete

@@ -5848,6 +5865,9 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
 			break;
 		}
 
+		if (unlikely(dev->flags & ATA_DFLAG_DUBIOUS_XFER))
+			ata_verify_xfer(qc);
+
 		__ata_qc_complete(qc);
 	} else {
 		if (qc->flags & ATA_QCFLAG_EH_SCHEDULED)

index cf2afb0..99231ec 100644
@@ -456,9 +456,20 @@ void ata_scsi_error(struct Scsi_Host *host)
 		spin_lock_irqsave(ap->lock, flags);
 
 		__ata_port_for_each_link(link, ap) {
+			struct ata_eh_context *ehc = &link->eh_context;
+			struct ata_device *dev;
+
 			memset(&link->eh_context, 0, sizeof(link->eh_context));
 			link->eh_context.i = link->eh_info;
 			memset(&link->eh_info, 0, sizeof(link->eh_info));
+
+			ata_link_for_each_dev(dev, link) {
+				int devno = dev->devno;
+
+				ehc->saved_xfer_mode[devno] = dev->xfer_mode;
+				if (ata_ncq_enabled(dev))
+					ehc->saved_ncq_enabled |= 1 << devno;
+			}
 		}
 
 		ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;

@@ -2439,11 +2450,27 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 {
 	struct ata_port *ap = link->ap;
+	struct ata_device *dev;
+	int rc;
 
 	/* has private set_mode? */
 	if (ap->ops->set_mode)
-		return ap->ops->set_mode(link, r_failed_dev);
-	return ata_do_set_mode(link, r_failed_dev);
+		rc = ap->ops->set_mode(link, r_failed_dev);
+	else
+		rc = ata_do_set_mode(link, r_failed_dev);
+
+	/* if transfer mode has changed, set DUBIOUS_XFER on device */
+	ata_link_for_each_dev(dev, link) {
+		struct ata_eh_context *ehc = &link->eh_context;
+		u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
+		u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
+
+		if (dev->xfer_mode != saved_xfer_mode ||
+		    ata_ncq_enabled(dev) != saved_ncq)
+			dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
+	}
+
+	return rc;
 }
 
 static int ata_link_nr_enabled(struct ata_link *link)

@@ -2504,6 +2531,8 @@ static int ata_eh_schedule_probe(struct ata_device *dev)
 	ata_dev_init(dev);
 	ehc->did_probe_mask |= (1 << dev->devno);
 	ehc->i.action |= ATA_EH_SOFTRESET;
+	ehc->saved_xfer_mode[dev->devno] = 0;
+	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
 	return 1;
 }

index 4abfb3c..7c34ff5 100644
@@ -141,6 +141,7 @@ enum {
 	ATA_DFLAG_NCQ_OFF	= (1 << 13), /* device limited to non-NCQ mode */
 	ATA_DFLAG_SPUNDOWN	= (1 << 14), /* XXX: for spindown_compat */
 	ATA_DFLAG_SLEEPING	= (1 << 15), /* device is sleeping */
+	ATA_DFLAG_DUBIOUS_XFER	= (1 << 16), /* data transfer not verified */
 	ATA_DFLAG_INIT_MASK	= (1 << 24) - 1,
 
 	ATA_DFLAG_DETACH	= (1 << 24),

@@ -555,6 +556,8 @@ struct ata_eh_context {
 	int			tries[ATA_MAX_DEVICES];
 	unsigned int		classes[ATA_MAX_DEVICES];
 	unsigned int		did_probe_mask;
+	unsigned int		saved_ncq_enabled;
+	u8			saved_xfer_mode[ATA_MAX_DEVICES];
 };
 
 struct ata_acpi_drive

index 99231ec..7835e1a 100644
@@ -50,16 +50,23 @@ enum {
 	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
 	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
 	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
+	ATA_EH_SPDN_KEEP_ERRORS		= (1 << 3),
 
 	/* error flags */
 	ATA_EFLAG_IS_IO			= (1 << 0),
+	ATA_EFLAG_DUBIOUS_XFER		= (1 << 1),
 
 	/* error categories */
 	ATA_ECAT_NONE			= 0,
 	ATA_ECAT_ATA_BUS		= 1,
 	ATA_ECAT_TOUT_HSM		= 2,
 	ATA_ECAT_UNK_DEV		= 3,
-	ATA_ECAT_NR			= 4,
+	ATA_ECAT_DUBIOUS_ATA_BUS	= 4,
+	ATA_ECAT_DUBIOUS_TOUT_HSM	= 5,
+	ATA_ECAT_DUBIOUS_UNK_DEV	= 6,
+	ATA_ECAT_NR			= 7,
+
+	ATA_ECAT_DUBIOUS_BASE		= ATA_ECAT_DUBIOUS_ATA_BUS,
 };
 
 /* Waiting in ->prereset can never be reliable.  It's sometimes nice

@@ -245,6 +252,15 @@ static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
 	ent->timestamp = get_jiffies_64();
 }
 
+static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
+{
+	struct ata_ering_entry *ent = &ering->ring[ering->cursor];
+
+	if (ent->err_mask)
+		return ent;
+	return NULL;
+}
+
 static void ata_ering_clear(struct ata_ering *ering)
 {
 	memset(ering, 0, sizeof(*ering));

@@ -1568,20 +1584,29 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
 	return action;
 }
 
-static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask)
+static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
+				   int *xfer_ok)
 {
+	int base = 0;
+
+	if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
+		*xfer_ok = 1;
+
+	if (!*xfer_ok)
+		base = ATA_ECAT_DUBIOUS_BASE;
+
 	if (err_mask & AC_ERR_ATA_BUS)
-		return ATA_ECAT_ATA_BUS;
+		return base + ATA_ECAT_ATA_BUS;
 
 	if (err_mask & AC_ERR_TIMEOUT)
-		return ATA_ECAT_TOUT_HSM;
+		return base + ATA_ECAT_TOUT_HSM;
 
 	if (eflags & ATA_EFLAG_IS_IO) {
 		if (err_mask & AC_ERR_HSM)
-			return ATA_ECAT_TOUT_HSM;
+			return base + ATA_ECAT_TOUT_HSM;
 		if ((err_mask &
 		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
-			return ATA_ECAT_UNK_DEV;
+			return base + ATA_ECAT_UNK_DEV;
 	}
 
 	return 0;

@@ -1589,18 +1614,22 @@ static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask)
 
 struct speed_down_verdict_arg {
 	u64 since;
+	int xfer_ok;
 	int nr_errors[ATA_ECAT_NR];
 };
 
 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
 {
 	struct speed_down_verdict_arg *arg = void_arg;
-	int cat = ata_eh_categorize_error(ent->eflags, ent->err_mask);
+	int cat;
 
 	if (ent->timestamp < arg->since)
 		return -1;
 
+	cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
+				      &arg->xfer_ok);
 	arg->nr_errors[cat]++;
+
 	return 0;
 }
 

@@ -1619,6 +1648,9 @@ static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
  *
  *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
  *
+ *	ECAT_DUBIOUS_*	: Identical to above three but occurred while
+ *			  data transfer hasn't been verified.
+ *
  *	Verdicts are
  *
  *	NCQ_OFF		: Turn off NCQ.

@@ -1629,15 +1661,27 @@ static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
  *	FALLBACK_TO_PIO	: Fall back to PIO.
  *
  *	Even if multiple verdicts are returned, only one action is
- *	taken per error.  ering is cleared after an action is taken.
+ *	taken per error.  An action triggered by non-DUBIOUS errors
+ *	clears ering, while one triggered by DUBIOUS_* errors doesn't.
+ *	This is to expedite speed down decisions right after device is
+ *	initially configured.
+ *
+ *	The followings are speed down rules.  #1 and #2 deal with
+ *	DUBIOUS errors.
  *
- *	1. If more than 6 ATA_BUS, TOUT_HSM or UNK_DEV errors
+ *	1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
+ *	   occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
+ *
+ *	2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
+ *	   occurred during last 5 mins, NCQ_OFF.
+ *
+ *	3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
  *	   ocurred during last 5 mins, FALLBACK_TO_PIO
  *
- *	2. If more than 3 TOUT_HSM or UNK_DEV errors occurred
+ *	4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
  *	   during last 10 mins, NCQ_OFF.
  *
- *	3. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
+ *	5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
  *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
  *
  *	LOCKING:

@@ -1658,6 +1702,15 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
 	arg.since = j64 - min(j64, j5mins);
 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
 
+	if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
+	    arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
+		verdict |= ATA_EH_SPDN_SPEED_DOWN |
+			ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;
+
+	if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
+	    arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
+		verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;
+
 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)

@@ -1701,11 +1754,12 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev,
 				unsigned int eflags, unsigned int err_mask)
 {
 	struct ata_link *link = dev->link;
+	int xfer_ok = 0;
 	unsigned int verdict;
 	unsigned int action = 0;
 
 	/* don't bother if Cat-0 error */
-	if (ata_eh_categorize_error(eflags, err_mask) == 0)
+	if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
 		return 0;
 
 	/* record error and determine whether speed down is necessary */

@@ -1768,7 +1822,8 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev,
 	return 0;
  done:
 	/* device has been slowed down, blow error history */
-	ata_ering_clear(&dev->ering);
+	if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
+		ata_ering_clear(&dev->ering);
 	return action;
 }
 

@@ -1874,8 +1929,11 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 	    ata_dev_enabled(link->device))
 		dev = link->device;
 
-	if (dev)
+	if (dev) {
+		if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
+			eflags |= ATA_EFLAG_DUBIOUS_XFER;
 		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
+	}
 
 	DPRINTK("EXIT\n");
 }

@@ -2453,6 +2511,17 @@ int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 	struct ata_device *dev;
 	int rc;
 
+	/* if data transfer is verified, clear DUBIOUS_XFER on ering top */
+	ata_link_for_each_dev(dev, link) {
+		if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
+			struct ata_ering_entry *ent;
+
+			ent = ata_ering_top(&dev->ering);
+			if (ent)
+				ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
+		}
+	}
+
 	/* has private set_mode? */
 	if (ap->ops->set_mode)
 		rc = ap->ops->set_mode(link, r_failed_dev);