Re: [PATCH v4] ata: libata: disable LPM for WDC WD20EFAX-68FB5N0 hard drives

[Niklas Cassel <cassel@kernel.org>]

Hello Mikko,

On Mon, May 12, 2025 at 01:34:38PM +0300, Mikko Juhani Korhonen wrote:

(snip)

> > Ok, so the bad 6.14.5 dmesg you shared before (where you got timeouts),
> > was when using SATA ports 5,6 ?
>
> Yes, and you can see in the logs, ataX matches the motherboard's SATA
> port number.
>
>
> > So, if we really want to have a quirk which disables LPM only for ports 5-6,
> > it would probably have to be a DMI quirk, which matches the motherboard name,
> > see e.g.:
> > https://github.com/torvalds/linux/blob/v6.15-rc6/drivers/ata/ahci.c#L1120-L1145
>
> And even this would disable LPM for the case of
> sata ports 5,6 -> WDC WD5000AAKX-001CA0
> which works now?

Oh, that drive works on ports 5-6 ?

I assumed that no drive that supports LPM worked on ports 5-6.
(And that you simply reported WD20EFAX-68FB5N0 because that is
what you had plugged in on that port originally.)


So you are saying that:
WD5000AAKX-001CA0 works with LPM enabled (lpm-pol 3), on port 5-6.
but
WD20EFAX-68FB5N0 gets timeouts with LPM enabled (lpm-pol 3), on port 5-6.

That is weird indeed.


From your earlier emails you have shared hdparm output from:
WD20EFAX-68FB5N0

which showed:
	Enabled		Supported
	*		Host-initiated interface power management
			Device-initiated interface power management

i.e. that HIPM and DIPM was supported, but only HIPM was enabled.
That is a bit weird, since you are using this on 6.14.5 and saw lpm-pol 3,
which means: ATA_LPM_MED_POWER_WITH_DIPM.

So I would have expected both HIPM and DIPM to have shown enabled in that
case, see:
https://github.com/torvalds/linux/blob/v6.15-rc6/drivers/ata/libata-eh.c#L3510-L3521


I could not find the similar hdparm output for WDC WD5000AAKX-001CA0.
Could you please post that as well?


Kind regards,
Niklas