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

[Niklas Cassel <cassel@kernel.org>]

On Sun, Mar 02, 2025 at 09:32:07PM +0100, Eric wrote:
> Hi Niklas,
> 
> Le 02/03/2025 à 20:32, Niklas Cassel a écrit :
> > On Sun, Mar 02, 2025 at 05:03:48PM +0100, Salvatore Bonaccorso wrote:
> > > Hi Mario et al,
> > > 
> > > Eric Degenetais reported in Debian (cf. https://bugs.debian.org/1091696) for
> > > his report, that after 7627a0edef54 ("ata: ahci: Drop low power policy  board
> > > type") rebooting the system fails (but system boots fine if cold booted).
> > > 
> > > 
> For what it's worth, before getting these replies I tested the
> ahci.mobile_lpm_policy=1 kernel parameter, which did work around the
> problem.

I'm glad that you have a workaround to make your system usable.


> > 
> > Eric is using the latest SSD fimware version. So from other peoples reports,
> > I would expect things to work for him as well.
> > 
> > However, no one has reported that their UEFI does not detect their SSD.
> > This seems to be either SSD firmware bug or UEFI bug.
> > 
> > I would expect your UEFI to send a COMRESET even during a reboot, and a
> > according to AHCI spec a COMRESET shall take the decide out of sleep states.
> > 
> > Considering that no one else seems to have any problem when using the latest
> > firmware version for this SSD, this seems to be a problem specific to Eric.
> > So... UEFI bug?
> > 
> > Have you tried updating your BIOS?
> 
> I had not tried to update my bios (bit shy on this due to a problem long ago
> with a power failure during bios update which left me with an unbootable
> machine).
> 
> However, as far as I see, there is no newer version of it.

Ok.

So far, this just sounds like a bug where UEFI cannot detect your SSD.
UEFI problems should be reported to your BIOS vendor.

It would be interesting to see if _Linux_ can detect your SSD, after a
reboot, without UEFI involvement.

If you kexec into the same kernel as you are currently running:
https://manpages.debian.org/testing/kexec-tools/kexec.8.en.html

Do you see your SSD in the kexec'd kernel?


Kind regards,
Niklas