libata: improve probe failure handling

* Move forcing device to PIO0 on device disable into
  ata_dev_disable().  This makes both old and new EHs act the same
  way.

* Speed down only PIO mode on probe failure.  All commands used during
  probing are PIO commands.  There's no point in speeding down DMA.

* Retry at least once after -ENODEV.  Some devices report garbled
  IDENTIFY data after certain events.  This shouldn't cause device
  detach and re-attach.

* Rearrange EH failure path for simplicity.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 249d487..24c6505 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -600,6 +600,8 @@ void ata_dev_disable(struct ata_device *dev)
 {
        if (ata_dev_enabled(dev) && ata_msg_drv(dev->ap)) {
                ata_dev_printk(dev, KERN_WARNING, "disabled\n");
+               ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 |
+                                            ATA_DNXFER_QUIET);
                dev->class++;
        }
 }
@@ -1778,9 +1780,8 @@ int ata_bus_probe(struct ata_port *ap)
 {
        unsigned int classes[ATA_MAX_DEVICES];
        int tries[ATA_MAX_DEVICES];
-       int i, rc, down_xfermask;
+       int i, rc;
        struct ata_device *dev;
-       int dnxfer_sel;
 
        ata_port_probe(ap);
 
@@ -1788,8 +1789,6 @@ int ata_bus_probe(struct ata_port *ap)
                tries[i] = ATA_PROBE_MAX_TRIES;
 
  retry:
-       down_xfermask = 0;
-
        /* reset and determine device classes */
        ap->ops->phy_reset(ap);
 
@@ -1837,10 +1836,8 @@ int ata_bus_probe(struct ata_port *ap)
 
        /* configure transfer mode */
        rc = ata_set_mode(ap, &dev);
-       if (rc) {
-               down_xfermask = 1;
+       if (rc)
                goto fail;
-       }
 
        for (i = 0; i < ATA_MAX_DEVICES; i++)
                if (ata_dev_enabled(&ap->device[i]))
@@ -1852,27 +1849,29 @@ int ata_bus_probe(struct ata_port *ap)
        return -ENODEV;
 
  fail:
+       tries[dev->devno]--;
+
        switch (rc) {
        case -EINVAL:
-       case -ENODEV:
+               /* eeek, something went very wrong, give up */
                tries[dev->devno] = 0;
                break;
+
+       case -ENODEV:
+               /* give it just one more chance */
+               tries[dev->devno] = min(tries[dev->devno], 1);
        case -EIO:
-               sata_down_spd_limit(ap);
-               /* fall through */
-       default:
-               tries[dev->devno]--;
-               dnxfer_sel = ATA_DNXFER_ANY;
-               if (tries[dev->devno] == 1)
-                       dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
-               if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
-                       tries[dev->devno] = 0;
+               if (tries[dev->devno] == 1) {
+                       /* This is the last chance, better to slow
+                        * down than lose it.
+                        */
+                       sata_down_spd_limit(ap);
+                       ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
+               }
        }
 
-       if (!tries[dev->devno]) {
-               ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0);
+       if (!tries[dev->devno])
                ata_dev_disable(dev);
-       }
 
        goto retry;
 }

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 7b61562..1abfdba 100644 (file)
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1964,8 +1964,7 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
 {
        struct ata_eh_context *ehc = &ap->eh_context;
        struct ata_device *dev;
-       int down_xfermask, i, rc;
-       int dnxfer_sel;
+       int i, rc;
 
        DPRINTK("ENTER\n");
 
@@ -1994,7 +1993,6 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
        }
 
  retry:
-       down_xfermask = 0;
        rc = 0;
 
        /* if UNLOADING, finish immediately */
@@ -2039,10 +2037,8 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
        /* configure transfer mode if necessary */
        if (ehc->i.flags & ATA_EHI_SETMODE) {
                rc = ata_set_mode(ap, &dev);
-               if (rc) {
-                       down_xfermask = 1;
+               if (rc)
                        goto dev_fail;
-               }
                ehc->i.flags &= ~ATA_EHI_SETMODE;
        }
 
@@ -2054,22 +2050,27 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
        goto out;
 
  dev_fail:
+       ehc->tries[dev->devno]--;
+
        switch (rc) {
-       case -ENODEV:
-               /* device missing, schedule probing */
-               ehc->i.probe_mask |= (1 << dev->devno);
        case -EINVAL:
+               /* eeek, something went very wrong, give up */
                ehc->tries[dev->devno] = 0;
                break;
+
+       case -ENODEV:
+               /* device missing or wrong IDENTIFY data, schedule probing */
+               ehc->i.probe_mask |= (1 << dev->devno);
+               /* give it just one more chance */
+               ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
        case -EIO:
-               sata_down_spd_limit(ap);
-       default:
-               ehc->tries[dev->devno]--;
-               dnxfer_sel = ATA_DNXFER_ANY;
-               if (ehc->tries[dev->devno] == 1)
-                       dnxfer_sel = ATA_DNXFER_FORCE_PIO0;
-               if (down_xfermask && ata_down_xfermask_limit(dev, dnxfer_sel))
-                       ehc->tries[dev->devno] = 0;
+               if (ehc->tries[dev->devno] == 1) {
+                       /* This is the last chance, better to slow
+                        * down than lose it.
+                        */
+                       sata_down_spd_limit(ap);
+                       ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
+               }
        }
 
        if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {