4 files changed, 53 insertions, 1 deletions

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index c6322c760348..498ff31f3aa1 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -328,3 +328,22 @@ Who:   Adrian Bunk <bunk@stusta.de>
 
 ---------------------------
 
+What: libata.spindown_compat module parameter
+When: Dec 2008
+Why:  halt(8) synchronizes caches for and spins down libata disks
+      because libata didn't use to spin down disk on system halt
+      (only synchronized caches).
+      Spin down on system halt is now implemented and can be tested
+      using sysfs node /sys/class/scsi_disk/h:c:i:l/manage_start_stop.
+      Because issuing spin down command to an already spun down disk
+      makes some disks spin up just to spin down again, the old
+      behavior needs to be maintained till userspace tool is updated
+      to check the sysfs node and not to spin down disks with the
+      node set to one.
+      This module parameter is to give userspace tool the time to
+      get updated and should be removed after userspace is
+      reasonably updated.
+Who:  Tejun Heo <htejun@gmail.com>
+
+---------------------------
+
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 2e2a2fa8e9e9..bf8f65b09591 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -101,6 +101,12 @@ int libata_noacpi = 1;
 module_param_named(noacpi, libata_noacpi, int, 0444);
 MODULE_PARM_DESC(noacpi, "Disables the use of ACPI in suspend/resume when set");
 
+int ata_spindown_compat = 1;
+module_param_named(spindown_compat, ata_spindown_compat, int, 0644);
+MODULE_PARM_DESC(spindown_compat, "Enable backward compatible spindown "
+                 "behavior.  Will be removed.  More info can be found in "
+                 "Documentation/feature-removal-schedule.txt\n");
+
 MODULE_AUTHOR("Jeff Garzik");
 MODULE_DESCRIPTION("Library module for ATA devices");
 MODULE_LICENSE("GPL");
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 8f800196d596..dd81fa78cdcf 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -944,9 +944,35 @@ static unsigned int ata_scsi_start_stop_xlat(struct ata_queued_cmd *qc)
                 }
 
                 tf->command = ATA_CMD_VERIFY;   /* READ VERIFY */
-        } else
+        } else {
+                /* XXX: This is for backward compatibility, will be
+                 * removed.  Read Documentation/feature-removal-schedule.txt
+                 * for more info.
+                 */
+                if (ata_spindown_compat &&
+                    (system_state == SYSTEM_HALT ||
+                     system_state == SYSTEM_POWER_OFF)) {
+                        static int warned = 0;
+
+                        if (!warned) {
+                                spin_unlock_irq(qc->ap->lock);
+                                ata_dev_printk(qc->dev, KERN_WARNING,
+                                        "DISK MIGHT NOT BE SPUN DOWN PROPERLY. "
+                                        "UPDATE SHUTDOWN UTILITY\n");
+                                ata_dev_printk(qc->dev, KERN_WARNING,
+                                        "For more info, visit "
+                                        "http://linux-ata.org/shutdown.html\n");
+                                warned = 1;
+                                ssleep(5);
+                                spin_lock_irq(qc->ap->lock);
+                        }
+                        scmd->result = SAM_STAT_GOOD;
+                        return 1;
+                }
+
                 /* Issue ATA STANDBY IMMEDIATE command */
                 tf->command = ATA_CMD_STANDBYNOW1;
+        }
 
         /*
          * Standby and Idle condition timers could be implemented but that
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 5f4d40cd3288..316bf8ae4536 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -58,6 +58,7 @@ extern int atapi_enabled;
 extern int atapi_dmadir;
 extern int libata_fua;
 extern int libata_noacpi;
+extern int ata_spindown_compat;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
 extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
                            u64 block, u32 n_block, unsigned int tf_flags,