Re: [PATCH v2] libata: Drop SanDisk SD7UB3Q*G1001 NOLPM quirk

[Tejun Heo]

On Thu, May 31, 2018 at 01:10:38PM +0100, Richard W.M. Jones wrote:
> On Thu, May 31, 2018 at 01:21:07PM +0200, Hans de Goede wrote:
> > Commit 184add2ca23c ("libata: Apply NOLPM quirk for SanDisk
> > SD7UB3Q*G1001 SSDs") disabled LPM for SanDisk SD7UB3Q*G1001 SSDs.
> > 
> > This has lead to several reports of users of that SSD where LPM
> > was working fine and who know have a significantly increased idle
> > power consumption on their laptops.
> > 
> > Likely there is another problem on the T450s from the original
> > reporter which gets exposed by the uncore reaching deeper sleep
> > states (higher PC-states) due to LPM being enabled. The problem as
> > reported, a hardfreeze about once a day, already did not sound like
> > it would be caused by LPM and the reports of the SSD working fine
> > confirm this. The original reporter is ok with dropping the quirk.
> > 
> > A X250 user has reported the same hard freeze problem and for him
> > the problem went away after unrelated updates, I suspect some GPU
> > driver stack changes fixed things.
> > 
> > TL;DR: The original reporters problem were triggered by LPM but not
> > an LPM issue, so drop the quirk for the SSD in question.
> 
> As the reporter of the original issue, I agree with Hans's
> analysis above, so ACK from me.

I'm not sure this is related but we were seeing periodic complete
lockups on "SanDisk SD[78]SN*G" devices with NCQ enabled and
blacklisted them for NCQ recently.

Thanks.

-- 
tejun