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

Niklas Cassel
2025-03-17T17:09:31Z

Hello Hans,

On Thu, Mar 13, 2025 at 07:47:11PM +0100, Hans de Goede wrote:
> 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.

I sent a patch that implements your original suggestion here:
https://lore.kernel.org/linux-ide/20250317170348.1748671-2-cassel@kernel.org/

I forgot to add your Suggested-by tag.
If the patch solves Eric's problem, I could add the tag when applying.

Kind regards,
Niklas