diff options
author | Hans de Goede <hdegoede@redhat.com> | 2017-09-14 13:35:36 +0300 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2017-09-19 06:22:04 +0300 |
commit | f4ac6476945ff62939420bcf8266e39f8d5d54bd (patch) | |
tree | 3428a2c2eeff5f7e8f63949914246add64721a90 | |
parent | 23e4c67ae13da7549a54f4e8c0014f48b2ef5204 (diff) | |
download | linux-f4ac6476945ff62939420bcf8266e39f8d5d54bd.tar.xz |
libata: Add new med_power_with_dipm link_power_management_policy setting
As described by Matthew Garret quite a while back:
https://mjg59.dreamwidth.org/34868.html
Intel CPUs starting with the Haswell generation need SATA links to power
down for the "package" part of the CPU to reach low power-states like
PC7 / P8 which bring a significant power-saving with them.
The default max_performance lpm policy does not allow for these high
PC states, both the medium_power and min_power policies do allow this.
The min_power policy saves significantly more power, but there are some
reports of some disks / SSDs not liking min_power leading to system
crashes and in some cases even data corruption has been reported.
Matthew has found a document documenting the default settings of
Intel's IRST Windows driver with which most laptops ship:
https://www-ssl.intel.com/content/dam/doc/reference-guide/sata-devices-implementation-recommendations.pdf
Matthew wrote a patch changing med_power to match those defaults, but
that never got anywhere as some people where reporting issues with the
patch-set that patch was a part of.
This commit is another attempt to make the default IRST driver settings
available under Linux, but instead of changing medium_power and
potentially introducing regressions, this commit adds a new
med_power_with_dipm setting which is identical to the existing
medium_power accept that it enables dipm on top, which makes it match
the Windows IRST driver settings, which should hopefully be safe to
use on most devices.
The med_power_with_dipm setting is close to min_power, except that:
a) It does not use host-initiated slumber mode (ASP not set),
but it does allow device-initiated slumber
b) It does not enable DevSlp mode
On my T440s test laptop I get the following power savings when idle:
medium_power 0.9W
med_power_with_dipm 1.2W
min_power 1.2W
Suggested-by: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r-- | drivers/ata/libata-core.c | 1 | ||||
-rw-r--r-- | drivers/ata/libata-eh.c | 10 | ||||
-rw-r--r-- | drivers/ata/libata-scsi.c | 9 | ||||
-rw-r--r-- | include/linux/libata.h | 1 |
4 files changed, 12 insertions, 9 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index ee4c1ec9dca0..65f7574afc55 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -3964,6 +3964,7 @@ int sata_link_scr_lpm(struct ata_link *link, enum ata_lpm_policy policy, scontrol &= ~(0x1 << 8); scontrol |= (0x6 << 8); break; + case ATA_LPM_MED_POWER_WITH_DIPM: case ATA_LPM_MIN_POWER: if (ata_link_nr_enabled(link) > 0) /* no restrictions on LPM transitions */ diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index e4effef0c83f..49b3745d2c1f 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -3454,9 +3454,9 @@ static int ata_eh_maybe_retry_flush(struct ata_device *dev) * @r_failed_dev: out parameter for failed device * * Enable SATA Interface power management. This will enable - * Device Interface Power Management (DIPM) for min_power - * policy, and then call driver specific callbacks for - * enabling Host Initiated Power management. + * Device Interface Power Management (DIPM) for min_power and + * medium_power_with_dipm policies, and then call driver specific + * callbacks for enabling Host Initiated Power management. * * LOCKING: * EH context. @@ -3502,7 +3502,7 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy, hints &= ~ATA_LPM_HIPM; /* disable DIPM before changing link config */ - if (policy != ATA_LPM_MIN_POWER && dipm) { + if (policy < ATA_LPM_MED_POWER_WITH_DIPM && dipm) { err_mask = ata_dev_set_feature(dev, SETFEATURES_SATA_DISABLE, SATA_DIPM); if (err_mask && err_mask != AC_ERR_DEV) { @@ -3545,7 +3545,7 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy, /* host config updated, enable DIPM if transitioning to MIN_POWER */ ata_for_each_dev(dev, link, ENABLED) { - if (policy == ATA_LPM_MIN_POWER && !no_dipm && + if (policy >= ATA_LPM_MED_POWER_WITH_DIPM && !no_dipm && ata_id_has_dipm(dev->id)) { err_mask = ata_dev_set_feature(dev, SETFEATURES_SATA_ENABLE, SATA_DIPM); diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 44ba292f2cd7..673e72f438eb 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -106,10 +106,11 @@ static const u8 def_control_mpage[CONTROL_MPAGE_LEN] = { }; static const char *ata_lpm_policy_names[] = { - [ATA_LPM_UNKNOWN] = "max_performance", - [ATA_LPM_MAX_POWER] = "max_performance", - [ATA_LPM_MED_POWER] = "medium_power", - [ATA_LPM_MIN_POWER] = "min_power", + [ATA_LPM_UNKNOWN] = "max_performance", + [ATA_LPM_MAX_POWER] = "max_performance", + [ATA_LPM_MED_POWER] = "medium_power", + [ATA_LPM_MED_POWER_WITH_DIPM] = "med_power_with_dipm", + [ATA_LPM_MIN_POWER] = "min_power", }; static ssize_t ata_scsi_lpm_store(struct device *device, diff --git a/include/linux/libata.h b/include/linux/libata.h index 931c32f1f18d..ed9826b21c5e 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -522,6 +522,7 @@ enum ata_lpm_policy { ATA_LPM_UNKNOWN, ATA_LPM_MAX_POWER, ATA_LPM_MED_POWER, + ATA_LPM_MED_POWER_WITH_DIPM, /* Med power + DIPM as win IRST does */ ATA_LPM_MIN_POWER, }; |