1 files changed, 72 insertions, 4 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 838ff73b08e1..fe3eba5d6b3e 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -219,6 +219,8 @@ enum {
 	AHCI_HFLAG_SECT255		= (1 << 8), /* max 255 sectors */
 	AHCI_HFLAG_YES_NCQ		= (1 << 9), /* force NCQ cap on */
 	AHCI_HFLAG_NO_SUSPEND		= (1 << 10), /* don't suspend */
+	AHCI_HFLAG_SRST_TOUT_IS_OFFLINE	= (1 << 11), /* treat SRST timeout as
+							link offline */
 
 	/* ap->flags bits */
 
@@ -1663,6 +1665,7 @@ static int ahci_do_softreset(struct ata_link *link, unsigned int *class,
 			     int (*check_ready)(struct ata_link *link))
 {
 	struct ata_port *ap = link->ap;
+	struct ahci_host_priv *hpriv = ap->host->private_data;
 	const char *reason = NULL;
 	unsigned long now, msecs;
 	struct ata_taskfile tf;
@@ -1701,12 +1704,21 @@ static int ahci_do_softreset(struct ata_link *link, unsigned int *class,
 
 	/* wait for link to become ready */
 	rc = ata_wait_after_reset(link, deadline, check_ready);
-	/* link occupied, -ENODEV too is an error */
-	if (rc) {
+	if (rc == -EBUSY && hpriv->flags & AHCI_HFLAG_SRST_TOUT_IS_OFFLINE) {
+		/*
+		 * Workaround for cases where link online status can't
+		 * be trusted.  Treat device readiness timeout as link
+		 * offline.
+		 */
+		ata_link_printk(link, KERN_INFO,
+				"device not ready, treating as offline\n");
+		*class = ATA_DEV_NONE;
+	} else if (rc) {
+		/* link occupied, -ENODEV too is an error */
 		reason = "device not ready";
 		goto fail;
-	}
-	*class = ahci_dev_classify(ap);
+	} else
+		*class = ahci_dev_classify(ap);
 
 	DPRINTK("EXIT, class=%u\n", *class);
 	return 0;
@@ -2727,6 +2739,56 @@ static bool ahci_broken_suspend(struct pci_dev *pdev)
 	return !ver || strcmp(ver, dmi->driver_data) < 0;
 }
 
+static bool ahci_broken_online(struct pci_dev *pdev)
+{
+#define ENCODE_BUSDEVFN(bus, slot, func)			\
+	(void *)(unsigned long)(((bus) << 8) | PCI_DEVFN((slot), (func)))
+	static const struct dmi_system_id sysids[] = {
+		/*
+		 * There are several gigabyte boards which use
+		 * SIMG5723s configured as hardware RAID.  Certain
+		 * 5723 firmware revisions shipped there keep the link
+		 * online but fail to answer properly to SRST or
+		 * IDENTIFY when no device is attached downstream
+		 * causing libata to retry quite a few times leading
+		 * to excessive detection delay.
+		 *
+		 * As these firmwares respond to the second reset try
+		 * with invalid device signature, considering unknown
+		 * sig as offline works around the problem acceptably.
+		 */
+		{
+			.ident = "EP45-DQ6",
+			.matches = {
+				DMI_MATCH(DMI_BOARD_VENDOR,
+					  "Gigabyte Technology Co., Ltd."),
+				DMI_MATCH(DMI_BOARD_NAME, "EP45-DQ6"),
+			},
+			.driver_data = ENCODE_BUSDEVFN(0x0a, 0x00, 0),
+		},
+		{
+			.ident = "EP45-DS5",
+			.matches = {
+				DMI_MATCH(DMI_BOARD_VENDOR,
+					  "Gigabyte Technology Co., Ltd."),
+				DMI_MATCH(DMI_BOARD_NAME, "EP45-DS5"),
+			},
+			.driver_data = ENCODE_BUSDEVFN(0x03, 0x00, 0),
+		},
+		{ }	/* terminate list */
+	};
+#undef ENCODE_BUSDEVFN
+	const struct dmi_system_id *dmi = dmi_first_match(sysids);
+	unsigned int val;
+
+	if (!dmi)
+		return false;
+
+	val = (unsigned long)dmi->driver_data;
+
+	return pdev->bus->number == (val >> 8) && pdev->devfn == (val & 0xff);
+}
+
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	static int printed_version;
@@ -2842,6 +2904,12 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 			   "BIOS update required for suspend/resume\n");
 	}
 
+	if (ahci_broken_online(pdev)) {
+		hpriv->flags |= AHCI_HFLAG_SRST_TOUT_IS_OFFLINE;
+		dev_info(&pdev->dev,
+			 "online status unreliable, applying workaround\n");
+	}
+
 	/* CAP.NP sometimes indicate the index of the last enabled
 	 * port, at other times, that of the last possible port, so
 	 * determining the maximum port number requires looking at