Re: [PATCH 3/6] ata: Fix SATA_MOBILE_LPM_POLICY description in Kconfig

[Hannes Reinecke <hare@suse.de>]

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@vger.kernel.org
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   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@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
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