[PATCH] nvme-pci: set some AMD PCIe downstream storage device to D3 for s2idle

[Christoph Hellwig]

On Wed, May 26, 2021 at 10:52:35AM +0200, Hans de Goede wrote:
> I see that the discussion has already continued without my thoughts (good),
> reading the further discussion I see that pm_suspend_via_firmware() and
> pm_suspend_no_platform() have already been mentioned. Using these (or
> introducing something similar for this use-case) was also my first
> thought on this (after the previous options were shot down).
> 
> So I think that looking at those is going in the right direction. I notice
> that Rafael Wysocki is missing from the Cc (I've added him now) I believe
> that this is something which is right up his alley and he might have some
> ideas on this.

I think providing some information to the driver that the platform
expects to power off the PCIe slots after ->suspend is called would
be extremely useful.  We already had to disable the intelligent suspend
support for all devices with a HMB because of it, which then caused another
regression because some platform/device combination get hickups when
put into D3cold.  I wish PM wasn't such a mess..