---

yaml
---
r: 130817
b: refs/heads/master
c: 9062712
h: refs/heads/master
i:
  130815: 2fdfc7c
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cf9a590a9eae3b99ca77d8db17afd2d7dbdd0986
+refs/heads/master: 9062712fa9ed13b531dfc2228086650b8bd6a255

trunk/drivers/ata/libata-core.c

@@ -2232,6 +2232,40 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
 	return rc;
 }
 
+static int ata_do_link_spd_horkage(struct ata_device *dev)
+{
+	struct ata_link *plink = ata_dev_phys_link(dev);
+	u32 target, target_limit;
+
+	if (!sata_scr_valid(plink))
+		return 0;
+
+	if (dev->horkage & ATA_HORKAGE_1_5_GBPS)
+		target = 1;
+	else
+		return 0;
+
+	target_limit = (1 << target) - 1;
+
+	/* if already on stricter limit, no need to push further */
+	if (plink->sata_spd_limit <= target_limit)
+		return 0;
+
+	plink->sata_spd_limit = target_limit;
+
+	/* Request another EH round by returning -EAGAIN if link is
+	 * going faster than the target speed.  Forward progress is
+	 * guaranteed by setting sata_spd_limit to target_limit above.
+	 */
+	if (plink->sata_spd > target) {
+		ata_dev_printk(dev, KERN_INFO,
+			       "applying link speed limit horkage to %s\n",
+			       sata_spd_string(target));
+		return -EAGAIN;
+	}
+	return 0;
+}
+
 static inline u8 ata_dev_knobble(struct ata_device *dev)
 {
 	struct ata_port *ap = dev->link->ap;
@@ -2322,6 +2356,10 @@ int ata_dev_configure(struct ata_device *dev)
 		return 0;
 	}
 
+	rc = ata_do_link_spd_horkage(dev);
+	if (rc)
+		return rc;
+
 	/* let ACPI work its magic */
 	rc = ata_acpi_on_devcfg(dev);
 	if (rc)
@@ -4223,6 +4261,9 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
 	/* Devices that do not need bridging limits applied */
 	{ "MTRON MSP-SATA*",		NULL,	ATA_HORKAGE_BRIDGE_OK, },
 
+	/* Devices which aren't very happy with higher link speeds */
+	{ "WD My Book",			NULL,	ATA_HORKAGE_1_5_GBPS, },
+
 	/* End Marker */
 	{ }
 };

trunk/include/linux/libata.h

@@ -380,6 +380,7 @@ enum {
 	ATA_HORKAGE_ATAPI_MOD16_DMA = (1 << 11), /* use ATAPI DMA for commands
 						    not multiple of 16 bytes */
 	ATA_HORKAGE_FIRMWARE_WARN = (1 << 12),	/* firwmare update warning */
+	ATA_HORKAGE_1_5_GBPS	= (1 << 13),	/* force 1.5 Gbps */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */