---

yaml
---
r: 130815
b: refs/heads/master
c: c2c7a89
h: refs/heads/master
i:
  130813: 83e4d2e
  130811: f6cee81
  130807: 2b71bb0
  130799: 684f09e
  130783: 719f019
  130751: 4b63be3
  130687: b1ab60a
  130559: 8813e85
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a07d499b4759881db1359dd8812eecd00b0e0a28
+refs/heads/master: c2c7a89c5eabaea8c0c2aa0c1069e510144513ab

trunk/drivers/ata/libata-eh.c

@@ -82,6 +82,10 @@ enum {
 	ATA_EH_FASTDRAIN_INTERVAL	=  3000,
 
 	ATA_EH_UA_TRIES			= 5,
+
+	/* probe speed down parameters, see ata_eh_schedule_probe() */
+	ATA_EH_PROBE_TRIAL_INTERVAL	= 60000,	/* 1 min */
+	ATA_EH_PROBE_TRIALS		= 2,
 };
 
 /* The following table determines how we sequence resets.  Each entry
@@ -2975,9 +2979,24 @@ static int ata_eh_skip_recovery(struct ata_link *link)
 	return 1;
 }
 
+static int ata_count_probe_trials_cb(struct ata_ering_entry *ent, void *void_arg)
+{
+	u64 interval = msecs_to_jiffies(ATA_EH_PROBE_TRIAL_INTERVAL);
+	u64 now = get_jiffies_64();
+	int *trials = void_arg;
+
+	if (ent->timestamp < now - min(now, interval))
+		return -1;
+
+	(*trials)++;
+	return 0;
+}
+
 static int ata_eh_schedule_probe(struct ata_device *dev)
 {
 	struct ata_eh_context *ehc = &dev->link->eh_context;
+	struct ata_link *link = ata_dev_phys_link(dev);
+	int trials = 0;
 
 	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
 	    (ehc->did_probe_mask & (1 << dev->devno)))
@@ -2990,6 +3009,25 @@ static int ata_eh_schedule_probe(struct ata_device *dev)
 	ehc->saved_xfer_mode[dev->devno] = 0;
 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
+	/* Record and count probe trials on the ering.  The specific
+	 * error mask used is irrelevant.  Because a successful device
+	 * detection clears the ering, this count accumulates only if
+	 * there are consecutive failed probes.
+	 *
+	 * If the count is equal to or higher than ATA_EH_PROBE_TRIALS
+	 * in the last ATA_EH_PROBE_TRIAL_INTERVAL, link speed is
+	 * forced to 1.5Gbps.
+	 *
+	 * This is to work around cases where failed link speed
+	 * negotiation results in device misdetection leading to
+	 * infinite DEVXCHG or PHRDY CHG events.
+	 */
+	ata_ering_record(&dev->ering, 0, AC_ERR_OTHER);
+	ata_ering_map(&dev->ering, ata_count_probe_trials_cb, &trials);
+
+	if (trials > ATA_EH_PROBE_TRIALS)
+		sata_down_spd_limit(link, 1);
+
 	return 1;
 }