[PATCH v5 1/2] PCI: add AMD PCIe quirk for nvme shutdown opt

[Deucher, Alexander]

[AMD Public Use]

> -----Original Message-----
> From: Keith Busch <kbusch at kernel.org>
> Sent: Thursday, May 20, 2021 2:04 PM
> To: Deucher, Alexander <Alexander.Deucher at amd.com>
> Cc: Bjorn Helgaas <helgaas at kernel.org>; Liang, Prike
> <Prike.Liang at amd.com>; linux-pci at vger.kernel.org; axboe at fb.com;
> hch at lst.de; sagi at grimberg.me; linux-nvme at lists.infradead.org;
> stable at vger.kernel.org; S-k, Shyam-sundar <Shyam-sundar.S-k at amd.com>;
> Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>; Rafael J. Wysocki
> <rjw at rjwysocki.net>; linux-pm at vger.kernel.org
> Subject: Re: [PATCH v5 1/2] PCI: add AMD PCIe quirk for nvme shutdown opt
> 
> On Thu, May 20, 2021 at 05:40:54PM +0000, Deucher, Alexander wrote:
> > It doesn't really have anything to do with PCI.  The PCI link is just
> > a proxy for specific AMD platforms.  It's platform firmware behavior
> > we are catering to.  This was originally posted as an nvme quirk, but
> > during the review it was recommended to move the quirk into PCI
> > because the quirk is not specific a particular NVMe device, but rather
> > a set of AMD platforms.  Lots of other platforms seems to do similar
> > things in the nvme driver based on ACPI or DMI flags, etc.  On our
> > hardware this nvme flag is required for all cezanne and renoir platforms.
> 
> The quirk was initially presented as specific to the pci root. Does it make
> more sense for nvme to recognize the limitation from querying a different
> platform component instead of the pci bus?

Maybe.  I'm not sure what the best way to tie this to a specific platform is.  @Limonciello, Mario?

Alex