On 6/27/25 03:11, Damien Le Moal wrote:
Improve the description of the possible default SATA link power
management policies and add the missing description for policy 5.
No functional changes.
Fixes: a5ec5a7bfd1f ("ata: ahci: Support state with min power but Partial low power state")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
drivers/ata/Kconfig | 36 ++++++++++++++++++++++++++----------
1 file changed, 26 insertions(+), 10 deletions(-)
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index e00536b49552..1d53d7b568bd 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -117,23 +117,39 @@ config SATA_AHCI
config SATA_MOBILE_LPM_POLICY
int "Default SATA Link Power Management policy"
- range 0 4
+ range 0 5
default 3
depends on SATA_AHCI
help
Select the Default SATA Link Power Management (LPM) policy to use
for chipsets / "South Bridges" supporting low-power modes. Such
chipsets are ubiquitous across laptops, desktops and servers.
-
- The value set has the following meanings:
+ Each policy combines power saving states and features:
+ - Partial: The Phy logic is powered but is in a reduced power
+ state. The exit latency from this state is no longer than
+ 10us).
+ - Slumber: The Phy logic is powered but is in an even lower power
+ state. The exit latency from this state is potentially
+ longer, but no longer than 10ms.
+ - DevSleep: The Phy logic may be powered down. The exit latency from
+ this state is no longer than 20 ms, unless otherwise
+ specified by DETO in the device Identify Device Data log.
+ - HIPM: Host Initiated Power Management (host automatic transisitons
+ to partial and slumber).
+ - DIPM: Device Initiated Power Management (device automatic
+ transitions to partial and slumber).
+
+ The possible values for the default SATA link power management
+ policies are:
0 => Keep firmware settings
- 1 => Maximum performance
- 2 => Medium power
- 3 => Medium power with Device Initiated PM enabled
- 4 => Minimum power
-
- Note "Minimum power" is known to cause issues, including disk
- corruption, with some disks and should not be used.
+ 1 => No power savings (maximum performance)
+ 2 => HIPM (Partial)
+ 3 => HIPM (Partial) and DIPM (Partial and Slumber)
+ 4 => HIPM (Partial and DevSleep) and DIPM (Partial and Slumber)
+ 5 => HIPM (Slumber and DevSleep) and DIPM (Partial and Slumber)
+
+ Excluding the value 0, higher values represent policies with higher
+ power savings.
config SATA_AHCI_PLATFORM
tristate "Platform AHCI SATA support"
Hmm. Isn't it worth creating an official documentation somewhere in
Documentation/* to have this available without having to look at the
source code?
Otherwise:
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
