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

Eric
2025-03-02T20:32:21Z

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.
> The model and fw version of the SSD.
>
> Anyway, I found it in the bug report:
> Device Model: Samsung SSD 870 QVO 2TB
> Firmware Version: SVQ02B6Q
>
> The firmware for this SSD is not great, and has caused us a lot of pain
> recently:
> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/ata?id=cc77e2ce187d26cc66af3577bf896d7410eb25ab
> https://lore.kernel.org/linux-ide/Z7xk1LbiYFAAsb9p@ryzen/T/#m831645f6cf2e6b528a8d531fa9b9f929dbf3d602
> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/ata?id=a2f925a2f62254119cdaa360cfc9c0424bccd531
>
>
> Basically, older firmware versions for this SSD have broken LPM, but from
> user reports, the latest firmware version (which Eric is using) is
> apparently working:
> https://bugzilla.kernel.org/show_bug.cgi?id=219747
> https://lore.kernel.org/stable/93c10d38-718c-459d-84a5-4d87680b4da7@debian.org/
>
>
> 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 :

My mobo model is :

sudo dmidecode -t 2

# dmidecode 3.4
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
Manufacturer: ASUSTeK COMPUTER INC.
Product Name: M5A99X EVO R2.0
Version: Rev 1.xx

From asus's website I get that the latest bios version for this model
is version

M5A99X EVO R2.0 BIOS 2501
Version 2501
3.06 MB
2014/05/14

And I appear to already use it :

sudo dmidecode -s bios-version
2501

>
>
> Kind regards,
> Niklas

kind regards,

Eric