[libata] Link power management infrastructure

Device Initiated Power Management, which is defined
in SATA 2.5 can be enabled for disks which support it.
This patch enables DIPM when the user sets the link
power management policy to "min_power".

Additionally, libata drivers can define a function
(enable_pm) that will perform hardware specific actions to
enable whatever power management policy the user set up
for Host Initiated Power management (HIPM).
This power management policy will be activated after all
disks have been enumerated and intialized.  Drivers should
also define disable_pm, which will turn off link power
management, but not change link power management policy.

Documentation/scsi/link_power_management_policy.txt has additional
information.

Signed-off-by:  Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index ec55d63cf20e..fefea7470e51 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2628,6 +2628,10 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                         ehc->i.flags &= ~ATA_EHI_SETMODE;
                 }
 
+                if (ehc->i.action & ATA_EHI_LPM)
+                        ata_link_for_each_dev(dev, link)
+                                ata_dev_enable_pm(dev, ap->pm_policy);
+
                 /* this link is okay now */
                 ehc->i.flags = 0;
                 continue;