[PATCH] nvme-pci: simple suspend quirk for vmd devices

[Rafael J. Wysocki]

On Wed, Feb 16, 2022 at 9:43 AM Christoph Hellwig <hch at lst.de> wrote:
>
> On Thu, Feb 10, 2022 at 07:22:33AM -0800, Keith Busch wrote:
> > Bug reports from users tell us platfroms with vmd enabled regressed
> > power when using nvme power management on s2idle. We can't get the
> > StorageD3Enable property on such devices so the driver used the wrong
> > suspend method. Add a simple suspend quirk for the domain since that is
> > the safest option.
> >
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=215467
> > Cc: "Rafael J. Wysocki" <rafael at kernel.org>
>
> Rafael, can you try this on the affected platform?
> (not for merge as-is)

I can't really do that myself (no access to the system in question),
but I've just asked the original reporter (CCed) to do it.

>
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index 9e1e6b8d88763..49f4e54da919d 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -723,4 +723,5 @@ struct pci_dev *pci_real_dma_dev(struct pci_dev *dev)
>
>         return dev;
>  }
> +EXPORT_SYMBOL_GPL(pci_real_dma_dev);
>  #endif
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 6a99ed6809158..6edc8c514cbc8 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -3086,7 +3086,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>
>         quirks |= check_vendor_combination_bug(pdev);
>
> -       if (!noacpi && acpi_storage_d3(&pdev->dev)) {
> +       if (!noacpi && acpi_storage_d3(&pci_real_dma_dev(pdev)->dev)) {
>                 /*
>                  * Some systems use a bios work around to ask for D3 on
>                  * platforms that support kernel managed suspend.