static struct device_attribute *ahci_sdev_attrs[] = {
        &dev_attr_sw_activity,
+       &dev_attr_unload_heads,
        NULL
 };
 
 
        INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan);
        INIT_LIST_HEAD(&ap->eh_done_q);
        init_waitqueue_head(&ap->eh_wait_q);
+       init_completion(&ap->park_req_pending);
        init_timer_deferrable(&ap->fastdrain_timer);
        ap->fastdrain_timer.function = ata_eh_fastdrain_timerfn;
        ap->fastdrain_timer.data = (unsigned long)ap;
 
        goto retry;
 }
 
+static inline void ata_eh_pull_park_action(struct ata_port *ap)
+{
+       struct ata_link *link;
+       struct ata_device *dev;
+       unsigned long flags;
+
+       /*
+        * This function can be thought of as an extended version of
+        * ata_eh_about_to_do() specially crafted to accommodate the
+        * requirements of ATA_EH_PARK handling. Since the EH thread
+        * does not leave the do {} while () loop in ata_eh_recover as
+        * long as the timeout for a park request to *one* device on
+        * the port has not expired, and since we still want to pick
+        * up park requests to other devices on the same port or
+        * timeout updates for the same device, we have to pull
+        * ATA_EH_PARK actions from eh_info into eh_context.i
+        * ourselves at the beginning of each pass over the loop.
+        *
+        * Additionally, all write accesses to &ap->park_req_pending
+        * through INIT_COMPLETION() (see below) or complete_all()
+        * (see ata_scsi_park_store()) are protected by the host lock.
+        * As a result we have that park_req_pending.done is zero on
+        * exit from this function, i.e. when ATA_EH_PARK actions for
+        * *all* devices on port ap have been pulled into the
+        * respective eh_context structs. If, and only if,
+        * park_req_pending.done is non-zero by the time we reach
+        * wait_for_completion_timeout(), another ATA_EH_PARK action
+        * has been scheduled for at least one of the devices on port
+        * ap and we have to cycle over the do {} while () loop in
+        * ata_eh_recover() again.
+        */
+
+       spin_lock_irqsave(ap->lock, flags);
+       INIT_COMPLETION(ap->park_req_pending);
+       ata_port_for_each_link(link, ap) {
+               ata_link_for_each_dev(dev, link) {
+                       struct ata_eh_info *ehi = &link->eh_info;
+
+                       link->eh_context.i.dev_action[dev->devno] |=
+                               ehi->dev_action[dev->devno] & ATA_EH_PARK;
+                       ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
+               }
+       }
+       spin_unlock_irqrestore(ap->lock, flags);
+}
+
+static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
+{
+       struct ata_eh_context *ehc = &dev->link->eh_context;
+       struct ata_taskfile tf;
+       unsigned int err_mask;
+
+       ata_tf_init(dev, &tf);
+       if (park) {
+               ehc->unloaded_mask |= 1 << dev->devno;
+               tf.command = ATA_CMD_IDLEIMMEDIATE;
+               tf.feature = 0x44;
+               tf.lbal = 0x4c;
+               tf.lbam = 0x4e;
+               tf.lbah = 0x55;
+       } else {
+               ehc->unloaded_mask &= ~(1 << dev->devno);
+               tf.command = ATA_CMD_CHK_POWER;
+       }
+
+       tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
+       tf.protocol |= ATA_PROT_NODATA;
+       err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
+       if (park && (err_mask || tf.lbal != 0xc4)) {
+               ata_dev_printk(dev, KERN_ERR, "head unload failed!\n");
+               ehc->unloaded_mask &= ~(1 << dev->devno);
+       }
+}
+
 static int ata_eh_revalidate_and_attach(struct ata_link *link,
                                        struct ata_device **r_failed_dev)
 {
        struct ata_device *dev;
        int nr_failed_devs;
        int rc;
-       unsigned long flags;
+       unsigned long flags, deadline;
 
        DPRINTK("ENTER\n");
 
                }
        }
 
+       do {
+               unsigned long now;
+
+               /*
+                * clears ATA_EH_PARK in eh_info and resets
+                * ap->park_req_pending
+                */
+               ata_eh_pull_park_action(ap);
+
+               deadline = jiffies;
+               ata_port_for_each_link(link, ap) {
+                       ata_link_for_each_dev(dev, link) {
+                               struct ata_eh_context *ehc = &link->eh_context;
+                               unsigned long tmp;
+
+                               if (dev->class != ATA_DEV_ATA)
+                                       continue;
+                               if (!(ehc->i.dev_action[dev->devno] &
+                                     ATA_EH_PARK))
+                                       continue;
+                               tmp = dev->unpark_deadline;
+                               if (time_before(deadline, tmp))
+                                       deadline = tmp;
+                               else if (time_before_eq(tmp, jiffies))
+                                       continue;
+                               if (ehc->unloaded_mask & (1 << dev->devno))
+                                       continue;
+
+                               ata_eh_park_issue_cmd(dev, 1);
+                       }
+               }
+
+               now = jiffies;
+               if (time_before_eq(deadline, now))
+                       break;
+
+               deadline = wait_for_completion_timeout(&ap->park_req_pending,
+                                                      deadline - now);
+       } while (deadline);
+       ata_port_for_each_link(link, ap) {
+               ata_link_for_each_dev(dev, link) {
+                       if (!(link->eh_context.unloaded_mask &
+                             (1 << dev->devno)))
+                               continue;
+
+                       ata_eh_park_issue_cmd(dev, 0);
+                       ata_eh_done(link, dev, ATA_EH_PARK);
+               }
+       }
+
        /* the rest */
        ata_port_for_each_link(link, ap) {
                struct ata_eh_context *ehc = &link->eh_context;
 
                ata_scsi_lpm_show, ata_scsi_lpm_put);
 EXPORT_SYMBOL_GPL(dev_attr_link_power_management_policy);
 
+static ssize_t ata_scsi_park_show(struct device *device,
+                                 struct device_attribute *attr, char *buf)
+{
+       struct scsi_device *sdev = to_scsi_device(device);
+       struct ata_port *ap;
+       struct ata_link *link;
+       struct ata_device *dev;
+       unsigned long flags;
+       unsigned int uninitialized_var(msecs);
+       int rc = 0;
+
+       ap = ata_shost_to_port(sdev->host);
+
+       spin_lock_irqsave(ap->lock, flags);
+       dev = ata_scsi_find_dev(ap, sdev);
+       if (!dev) {
+               rc = -ENODEV;
+               goto unlock;
+       }
+       if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
+               rc = -EOPNOTSUPP;
+               goto unlock;
+       }
+
+       link = dev->link;
+       if (ap->pflags & ATA_PFLAG_EH_IN_PROGRESS &&
+           link->eh_context.unloaded_mask & (1 << dev->devno) &&
+           time_after(dev->unpark_deadline, jiffies))
+               msecs = jiffies_to_msecs(dev->unpark_deadline - jiffies);
+       else
+               msecs = 0;
+
+unlock:
+       spin_unlock_irq(ap->lock);
+
+       return rc ? rc : snprintf(buf, 20, "%u\n", msecs);
+}
+
+static ssize_t ata_scsi_park_store(struct device *device,
+                                  struct device_attribute *attr,
+                                  const char *buf, size_t len)
+{
+       struct scsi_device *sdev = to_scsi_device(device);
+       struct ata_port *ap;
+       struct ata_device *dev;
+       long int input;
+       unsigned long flags;
+       int rc;
+
+       rc = strict_strtol(buf, 10, &input);
+       if (rc || input < -2)
+               return -EINVAL;
+       if (input > ATA_TMOUT_MAX_PARK) {
+               rc = -EOVERFLOW;
+               input = ATA_TMOUT_MAX_PARK;
+       }
+
+       ap = ata_shost_to_port(sdev->host);
+
+       spin_lock_irqsave(ap->lock, flags);
+       dev = ata_scsi_find_dev(ap, sdev);
+       if (unlikely(!dev)) {
+               rc = -ENODEV;
+               goto unlock;
+       }
+       if (dev->class != ATA_DEV_ATA) {
+               rc = -EOPNOTSUPP;
+               goto unlock;
+       }
+
+       if (input >= 0) {
+               if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
+                       rc = -EOPNOTSUPP;
+                       goto unlock;
+               }
+
+               dev->unpark_deadline = ata_deadline(jiffies, input);
+               dev->link->eh_info.dev_action[dev->devno] |= ATA_EH_PARK;
+               ata_port_schedule_eh(ap);
+               complete(&ap->park_req_pending);
+       } else {
+               switch (input) {
+               case -1:
+                       dev->flags &= ~ATA_DFLAG_NO_UNLOAD;
+                       break;
+               case -2:
+                       dev->flags |= ATA_DFLAG_NO_UNLOAD;
+                       break;
+               }
+       }
+unlock:
+       spin_unlock_irqrestore(ap->lock, flags);
+
+       return rc ? rc : len;
+}
+DEVICE_ATTR(unload_heads, S_IRUGO | S_IWUSR,
+           ata_scsi_park_show, ata_scsi_park_store);
+EXPORT_SYMBOL_GPL(dev_attr_unload_heads);
+
 static void ata_scsi_set_sense(struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq)
 {
        cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
                        ata_scsi_activity_store);
 EXPORT_SYMBOL_GPL(dev_attr_sw_activity);
 
+struct device_attribute *ata_common_sdev_attrs[] = {
+       &dev_attr_unload_heads,
+       NULL
+};
+EXPORT_SYMBOL_GPL(ata_common_sdev_attrs);
+
 static void ata_scsi_invalid_field(struct scsi_cmnd *cmd,
                                   void (*done)(struct scsi_cmnd *))
 {
 static int ata_scsi_dev_config(struct scsi_device *sdev,
                               struct ata_device *dev)
 {
+       if (!ata_id_has_unload(dev->id))
+               dev->flags |= ATA_DFLAG_NO_UNLOAD;
+
        /* configure max sectors */
        blk_queue_max_sectors(sdev->request_queue, dev->max_sectors);
 
 
        ATA_DFLAG_SPUNDOWN      = (1 << 14), /* XXX: for spindown_compat */
        ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
        ATA_DFLAG_DUBIOUS_XFER  = (1 << 16), /* data transfer not verified */
+       ATA_DFLAG_NO_UNLOAD     = (1 << 17), /* device doesn't support unload */
        ATA_DFLAG_INIT_MASK     = (1 << 24) - 1,
 
        ATA_DFLAG_DETACH        = (1 << 24),
        ATA_TMOUT_BOOT          = 30000,        /* heuristic */
        ATA_TMOUT_BOOT_QUICK    =  7000,        /* heuristic */
        ATA_TMOUT_INTERNAL_QUICK = 5000,
+       ATA_TMOUT_MAX_PARK      = 30000,
 
        /* FIXME: GoVault needs 2s but we can't afford that without
         * parallel probing.  800ms is enough for iVDR disk
        ATA_EH_RESET            = ATA_EH_SOFTRESET | ATA_EH_HARDRESET,
        ATA_EH_ENABLE_LINK      = (1 << 3),
        ATA_EH_LPM              = (1 << 4),  /* link power management action */
+       ATA_EH_PARK             = (1 << 5), /* unload heads and stop I/O */
 
-       ATA_EH_PERDEV_MASK      = ATA_EH_REVALIDATE,
+       ATA_EH_PERDEV_MASK      = ATA_EH_REVALIDATE | ATA_EH_PARK,
        ATA_EH_ALL_ACTIONS      = ATA_EH_REVALIDATE | ATA_EH_RESET |
                                  ATA_EH_ENABLE_LINK | ATA_EH_LPM,
 
        MEDIUM_POWER,
 };
 extern struct device_attribute dev_attr_link_power_management_policy;
+extern struct device_attribute dev_attr_unload_heads;
 extern struct device_attribute dev_attr_em_message_type;
 extern struct device_attribute dev_attr_em_message;
 extern struct device_attribute dev_attr_sw_activity;
        /* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
        u64                     n_sectors;      /* size of device, if ATA */
        unsigned int            class;          /* ATA_DEV_xxx */
+       unsigned long           unpark_deadline;
 
        u8                      pio_mode;
        u8                      dma_mode;
                                               [ATA_EH_CMD_TIMEOUT_TABLE_SIZE];
        unsigned int            classes[ATA_MAX_DEVICES];
        unsigned int            did_probe_mask;
+       unsigned int            unloaded_mask;
        unsigned int            saved_ncq_enabled;
        u8                      saved_xfer_mode[ATA_MAX_DEVICES];
        /* timestamp for the last reset attempt or success */
        struct list_head        eh_done_q;
        wait_queue_head_t       eh_wait_q;
        int                     eh_tries;
+       struct completion       park_req_pending;
 
        pm_message_t            pm_mesg;
        int                     *pm_result;
  */
 extern const struct ata_port_operations ata_base_port_ops;
 extern const struct ata_port_operations sata_port_ops;
+extern struct device_attribute *ata_common_sdev_attrs[];
 
 #define ATA_BASE_SHT(drv_name)                                 \
        .module                 = THIS_MODULE,                  \
        .proc_name              = drv_name,                     \
        .slave_configure        = ata_scsi_slave_config,        \
        .slave_destroy          = ata_scsi_slave_destroy,       \
-       .bios_param             = ata_std_bios_param
+       .bios_param             = ata_std_bios_param,           \
+       .sdev_attrs             = ata_common_sdev_attrs
 
 #define ATA_NCQ_SHT(drv_name)                                  \
        ATA_BASE_SHT(drv_name),                                 \