libata: Power off empty ports
Give users the option of completely powering off unoccupied
SATA ports using the existing min_power link_power_management_policy
option. When the use selects this option on an empty port, we
will power the port off by setting DET to off. For occupied ports,
behavior is unchanged.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 76c3c15..736bee5 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3619,8 +3619,14 @@
scontrol |= (0x2 << 8);
break;
case ATA_LPM_MIN_POWER:
- /* no restrictions on LPM transitions */
- scontrol &= ~(0x3 << 8);
+ if (ata_link_nr_enabled(link) > 0)
+ /* no restrictions on LPM transitions */
+ scontrol &= ~(0x3 << 8);
+ else {
+ /* empty port, power off */
+ scontrol &= ~0xf;
+ scontrol |= (0x1 << 2);
+ }
break;
default:
WARN_ON(1);
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index dad9fd6..dfb6e9d 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -3423,7 +3423,7 @@
return rc;
}
-static int ata_link_nr_enabled(struct ata_link *link)
+int ata_link_nr_enabled(struct ata_link *link)
{
struct ata_device *dev;
int cnt = 0;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 04f32a3..5a9926b 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1151,6 +1151,7 @@
ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
ata_postreset_fn_t postreset);
extern void ata_std_error_handler(struct ata_port *ap);
+extern int ata_link_nr_enabled(struct ata_link *link);
/*
* Base operations to inherit from and initializers for sht