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 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).
> 
> His report mentions that the SSD is not seen on warm reboots anymore.
> 
> Does this ring some bell which might be caused by the above bisected[1] commit?
> 
> #regzbot introduced: 7627a0edef54
> #regzbot link: https://bugs.debian.org/1091696
> 
> What information to you could be helpful to identify 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?


Kind regards,
Niklas