Re: [Regression] Commit "nvme/pci: Use host managed power state for suspend" has problems

["Rafael J. Wysocki" <rafael@kernel.org>]

On Mon, Aug 5, 2019 at 9:14 PM Kai-Heng Feng
<kai.heng.feng@canonical.com> wrote:
>
> at 19:04, Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> > On Fri, Aug 2, 2019 at 12:55 PM Kai-Heng Feng
> > <kai.heng.feng@canonical.com> wrote:
> >> at 06:26, Rafael J. Wysocki <rafael@kernel.org> wrote:
> >>
> >>> On Thu, Aug 1, 2019 at 9:05 PM <Mario.Limonciello@dell.com> wrote:
> >>>>> -----Original Message-----
> >>>>> From: Rafael J. Wysocki <rafael@kernel.org>
> >>>>> Sent: Thursday, August 1, 2019 12:30 PM
> >>>>> To: Kai-Heng Feng; Keith Busch; Limonciello, Mario
> >>>>> Cc: Keith Busch; Christoph Hellwig; Sagi Grimberg; linux-nvme; Linux
> >>>>> PM; Linux
> >>>>> Kernel Mailing List; Rajat Jain
> >>>>> Subject: Re: [Regression] Commit "nvme/pci: Use host managed power
> >>>>> state for
> >>>>> suspend" has problems
> >>>>>
> >>>>>
> >>>>> [EXTERNAL EMAIL]
> >>>>>
> >>>>> On Thu, Aug 1, 2019 at 11:06 AM Kai-Heng Feng
> >>>>> <kai.heng.feng@canonical.com> wrote:
> >>>>>> at 06:33, Rafael J. Wysocki <rafael@kernel.org> wrote:
> >>>>>>
> >>>>>>> On Thu, Aug 1, 2019 at 12:22 AM Keith Busch <kbusch@kernel.org>
> >>>>>>> wrote:
> >>>>>>>> On Wed, Jul 31, 2019 at 11:25:51PM +0200, Rafael J. Wysocki wrote:
> >>>>>>>>> A couple of remarks if you will.
> >>>>>>>>>
> >>>>>>>>> First, we don't know which case is the majority at this point.  For
> >>>>>>>>> now, there is one example of each, but it may very well turn out
> >>>>>>>>> that
> >>>>>>>>> the SK Hynix BC501 above needs to be quirked.
> >>>>>>>>>
> >>>>>>>>> Second, the reference here really is 5.2, so if there are any
> >>>>>>>>> systems
> >>>>>>>>> that are not better off with 5.3-rc than they were with 5.2,
> >>>>>>>>> well, we
> >>>>>>>>> have not made progress.  However, if there are systems that are
> >>>>>>>>> worse
> >>>>>>>>> off with 5.3, that's bad.  In the face of the latest findings the
> >>>>>>>>> only
> >>>>>>>>> way to avoid that is to be backwards compatible with 5.2 and that's
> >>>>>>>>> where my patch is going.  That cannot be achieved by quirking all
> >>>>>>>>> cases that are reported as "bad", because there still may be
> >>>>>>>>> unreported ones.
> >>>>>>>>
> >>>>>>>> I have to agree. I think your proposal may allow PCI D3cold,
> >>>>>>>
> >>>>>>> Yes, it may.
> >>>>>>
> >>>>>> Somehow the 9380 with Toshiba NVMe never hits SLP_S0 with or without
> >>>>>> Rafael’s patch.
> >>>>>> But the “real” s2idle power consumption does improve with the patch.
> >>>>>
> >>>>> Do you mean this patch:
> >>>>>
> >>>>> https://lore.kernel.org/linux-pm/70D536BE-8DC7-4CA2-84A9-
> >>>>> AFB067BA520E@canonical.com/T/#m456aa5c69973a3b68f2cdd4713a1ce83be5145
> >>>>> 8f
> >>>>>
> >>>>> or the $subject one without the above?
> >>>>>
> >>>>>> Can we use a DMI based quirk for this platform? It seems like a
> >>>>>> platform
> >>>>>> specific issue.
> >>>>>
> >>>>> We seem to see too many "platform-specific issues" here. :-)
> >>>>>
> >>>>> To me, the status quo (ie. what we have in 5.3-rc2) is not defensible.
> >>>>> Something needs to be done to improve the situation.
> >>>>
> >>>> Rafael, would it be possible to try popping out PC401 from the 9380 and
> >>>> into a 9360 to
> >>>> confirm there actually being a platform impact or not?
> >>>
> >>> Not really, sorry.
> >>>
> >>>> I was hoping to have something useful from Hynix by now before
> >>>> responding, but oh well.
> >>>>
> >>>> In terms of what is the majority, I do know that between folks at Dell,
> >>>> Google, Compal,
> >>>> Wistron, Canonical, Micron, Hynix, Toshiba, LiteOn, and Western Digital
> >>>> we tested a wide
> >>>> variety of SSDs with this patch series.  I would like to think that they
> >>>> are representative of
> >>>> what's being manufactured into machines now.
> >>>
> >>> Well, what about drives already in the field?  My concern is mostly
> >>> about those ones.
> >>>
> >>>> Notably the LiteOn CL1 was tested with the HMB flushing support and
> >>>> and Hynix PC401 was tested with older firmware though.
> >>>>
> >>>>>>>> In which case we do need to reintroduce the HMB handling.
> >>>>>>>
> >>>>>>> Right.
> >>>>>>
> >>>>>> The patch alone doesn’t break HMB Toshiba NVMe I tested. But I think
> >>>>>> it’s
> >>>>>> still safer to do proper HMB handling.
> >>>>>
> >>>>> Well, so can anyone please propose something specific?  Like an
> >>>>> alternative patch?
> >>>>
> >>>> This was proposed a few days ago:
> >>>> http://lists.infradead.org/pipermail/linux-nvme/2019-July/026056.html
> >>>>
> >>>> However we're still not sure why it is needed, and it will take some
> >>>> time to get
> >>>> a proper failure analysis from LiteOn  regarding the CL1.
> >>>
> >>> Thanks for the update, but IMO we still need to do something before
> >>> final 5.3 while the investigation continues.
> >>>
> >>> Honestly, at this point I would vote for going back to the 5.2
> >>> behavior at least by default and only running the new code on the
> >>> drives known to require it (because they will block PC10 otherwise).
> >>>
> >>> Possibly (ideally) with an option for users who can't get beyond PC3
> >>> to test whether or not the new code helps them.
> >>
> >> I just found out that the XPS 9380 at my hand never reaches SLP_S0 but
> >> only
> >> PC10.
> >
> > That's the case for me too.
> >
> >> This happens with or without putting the device to D3.
> >
> > On my system, though, it only can get to PC3 without putting the NVMe
> > into D3 (as reported previously).
>
> I forgot to ask, what BIOS version does the system have?
> I don’t see this issue on BIOS v1.5.0.

It is 1.5.0 here too.