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

[Kai-Heng Feng]

at 06:33, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote:

> On Thu, Aug 1, 2019 at 12:22 AM Keith Busch <kbusch@xxxxxxxxxx> 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  
Rafaelâs patch.
But the ârealâ s2idle power consumption does improve with the patch.

Can we use a DMI based quirk for this platform? It seems like a platform  
specific issue.

> > In which case we do need to reintroduce the HMB handling.
>
> Right.

The patch alone doesnât break HMB Toshiba NVMe I tested. But I think itâs  
still safer to do proper HMB handling.

Kai-Heng