Re: Regression from 7627a0edef54 ("ata: ahci: Drop low power policy board type") on reboot (but not cold boot)

Hans de Goede
2025-03-13T18:47:16Z

Hi,

On 13-Mar-25 4:28 PM, Niklas Cassel wrote:
> Hello Hans,
>
> On Thu, Mar 13, 2025 at 04:13:24PM +0100, Hans de Goede wrote:
>>>
>>> Considering that DIPM seems to work fine on the Maxtor drive, I guess your
>>> initial suggestion of a Samsung only quirk which only disables LPM on ATI
>>> is the best way?
>>
>> I have no objections against going that route, except that I guess this
>> should then be something like ATA_QUIRK_NO_DIPM_ON_ATI to not loose the
>> other LPM modes / savings? AFAIK/IIRC there still is quite some powersaving
>> to be had without DIPM.
>
> I was thinking like your original suggestion, i.e. setting:
> ATA_QUIRK_NO_LPM_ON_ATI
>
> for all the Samsung devices that currently have:
> ATA_QUIRK_NO_NCQ_ON_ATI
>
> Considering that this Samsung device only supports DIPM
> (and not HIPM), I'm guessing the same is true for the other
> Samsung devices as well.

Ah I see ...

> So we might as well just do:
> ATA_QUIRK_NO_LPM_ON_ATI

Yes I agree and that will nicely work as a combination of
ATA_QUIRK_NO_LPM + ATA_QUIRK_NO_NCQ_ON_ATI functionality
so using tested code-paths in a slightly new way.

Regards,

Hans

> to disable both HIPM and DIPM
> (since only DIPM would have been enabled without this quirk anyway).
>
>
>> Yes the most severe problems do seem to come from that specific mix,
>> although the long list of other ATI controller quirks also shows those
>> controllers are somewhat finicky.
>
> Definitely!
>
>
> Kind regards,
> Niklas
>