ata: Fix SATA_MOBILE_LPM_POLICY description in Kconfig

[ Upstream commit ed62a62a18bc144f73eadf866ae46842e8f6606e ]

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>
[ Adjust context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index d9b305a3427f7751e6a5a714137c71160b2ef4c9..5f96d15e0c09d1e657f8b3cb48ab62a9318c9dcc 100644 (file)
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -117,7 +117,7 @@ config SATA_AHCI
 
 config SATA_MOBILE_LPM_POLICY
        int "Default SATA Link Power Management policy for low power chipsets"
-       range 0 4
+       range 0 5
        default 0
        depends on SATA_AHCI
        help
@@ -126,15 +126,32 @@ config SATA_MOBILE_LPM_POLICY
          chipsets are typically found on most laptops but desktops and
          servers now also widely use chipsets supporting low power modes.
 
-         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"