4 files changed, 40 insertions, 7 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 090abe443820..21f8d61e5879 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1272,9 +1272,20 @@ int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
 
         tf.protocol = ATA_PROT_PIO;
 
+        /* presence detection using polling IDENTIFY? */
+        if (flags & ATA_READID_DETECT)
+                tf.flags |= ATA_TFLAG_POLLING;
+
         err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
                                      id, sizeof(id[0]) * ATA_ID_WORDS);
         if (err_mask) {
+                if ((flags & ATA_READID_DETECT) &&
+                    (err_mask & AC_ERR_NODEV_HINT)) {
+                        DPRINTK("ata%u.%d: NODEV after polling detection\n",
+                                ap->id, dev->devno);
+                        return -ENOENT;
+                }
+
                 rc = -EIO;
                 reason = "I/O error";
                 goto err_out;
@@ -4285,8 +4296,12 @@ fsm_start:
                                         /* device stops HSM for abort/error */
                                         qc->err_mask |= AC_ERR_DEV;
                                 else
-                                        /* HSM violation. Let EH handle this */
-                                        qc->err_mask |= AC_ERR_HSM;
+                                        /* HSM violation. Let EH handle this.
+                                         * Phantom devices also trigger this
+                                         * condition.  Mark hint.
+                                         */
+                                        qc->err_mask |= AC_ERR_HSM |
+                                                        AC_ERR_NODEV_HINT;
 
                                 ap->hsm_task_state = HSM_ST_ERR;
                                 goto fsm_start;
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 755fc68b5374..e69f3df2ea39 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1667,12 +1667,23 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
                            ata_class_enabled(ehc->classes[dev->devno])) {
                         dev->class = ehc->classes[dev->devno];
 
+                        if (ap->flags & ATA_FLAG_DETECT_POLLING)
+                                readid_flags |= ATA_READID_DETECT;
+
                         rc = ata_dev_read_id(dev, &dev->class, readid_flags,
                                              dev->id);
                         if (rc == 0) {
                                 ehc->i.flags |= ATA_EHI_PRINTINFO;
                                 rc = ata_dev_configure(dev);
                                 ehc->i.flags &= ~ATA_EHI_PRINTINFO;
+                        } else if (rc == -ENOENT) {
+                                /* IDENTIFY was issued to non-existent
+                                 * device.  No need to reset.  Just
+                                 * thaw and kill the device.
+                                 */
+                                ata_eh_thaw_port(ap);
+                                dev->class = ATA_DEV_UNKNOWN;
+                                rc = 0;
                         }
 
                         if (rc) {
@@ -1680,12 +1691,14 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
                                 break;
                         }
 
-                        spin_lock_irqsave(ap->lock, flags);
-                        ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
-                        spin_unlock_irqrestore(ap->lock, flags);
+                        if (ata_dev_enabled(dev)) {
+                                spin_lock_irqsave(ap->lock, flags);
+                                ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
+                                spin_unlock_irqrestore(ap->lock, flags);
 
-                        /* new device discovered, configure transfer mode */
-                        ehc->i.flags |= ATA_EHI_SETMODE;
+                                /* new device discovered, configure xfermode */
+                                ehc->i.flags |= ATA_EHI_SETMODE;
+                        }
                 }
         }
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index bb98390aa01a..be2ac39f013b 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -42,6 +42,8 @@ struct ata_scsi_args {
 enum {
         /* flags for ata_dev_read_id() */
         ATA_READID_POSTRESET    = (1 << 0), /* reading ID after reset */
+        ATA_READID_DETECT       = (1 << 1), /* perform presence detection
+                                             * using polling IDENTIFY */
 };
 
 extern struct workqueue_struct *ata_aux_wq;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 36e233cc3886..9080789913f7 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -176,6 +176,8 @@ enum {
         ATA_FLAG_SKIP_D2H_BSY   = (1 << 12), /* can't wait for the first D2H
                                               * Register FIS clearing BSY */
         ATA_FLAG_DEBUGMSG       = (1 << 13),
+        ATA_FLAG_DETECT_POLLING = (1 << 14), /* detect device presence by
+                                              * polling IDENTIFY */
 
         /* The following flag belongs to ap->pflags but is kept in
          * ap->flags because it's referenced in many LLDs and will be
@@ -335,6 +337,7 @@ enum ata_completion_errors {
         AC_ERR_SYSTEM           = (1 << 6), /* system error */
         AC_ERR_INVALID          = (1 << 7), /* invalid argument */
         AC_ERR_OTHER            = (1 << 8), /* unknown */
+        AC_ERR_NODEV_HINT       = (1 << 9), /* polling device detection hint */
 };
 
 /* forward declarations */