[PATCH] nvme/pci: default to simple suspend

[Keith Busch]

On Tue, Feb 08, 2022 at 03:37:51PM +0100, Christoph Hellwig wrote:
> On Mon, Feb 07, 2022 at 08:06:55AM -0800, Keith Busch wrote:
> > > I'd really prefer to sort this out at the platform level.  We can't work
> > > around broken platforms in nvme forever.
> > 
> > I agree, but I'm not sure how to get everyone aligned.
> > 
> > How about this to resolve the regressions: if the platform doesn't
> > provide StorageD3Enable property, can we just default to the simple
> > shutdown method? We'd only use the nvme power management capabilities if
> > the platform explicity says it doesn't want D3, making the default the
> > same as the legacy behavior.
> 
> I don't think this will work, as most older platforms just won't have
> that attribute at all, and non-ACPI platforms most certainly won't have
> it.  We'll need more quirks in the core PCI/PM code like we did for the
> AMD mobile platforms.

 old platform + old kernel -> simple suspend

 old platform + new kernel -> nvme pm

This inevitably introduced regressions. Why should we need to quirk old
platforms for a feature that didn't even exist when they were made?
Shouldn't the quirk be the other way around?