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