ata: Fix SATA_MOBILE_LPM_POLICY description in Kconfig

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@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Niklas Cassel <cassel@kernel.org>

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index e00536b495529b5bd865fed8b0f6b93793419c61..120a2b7067fc7b90dbe33de27b17d52e3081cbbc 100644 (file)
--- 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 automatically
+                  transitions to partial and slumber).
+          - DIPM: Device Initiated Power Management (device automatically
+                  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"