[PATCH v3] nvme/pci: Add quick suspend quirk for Sc7280 Platform

[Nitin Rawat (QUIC)]

Hi Christoph/Keith/Rafael

Since we are giving control to PCIe (NVMe power rails control), it can vary from platform to platform.
More over, PCIe driver doesn't control these power rails directly from PCIe driver, they tie nvme supply with one of the pcie supply and control them together. 
So i think it would be better to either have quirk based on platform or always setting simple suspend and platform which needs full suspend can update it through some means. 

Based on below link, Looks like this can be across platform ...vidya also mention similar concern for tegra platform.  
https://lore.kernel.org/lkml/20220209202639.GB1616420@dhcp-10-100-145-180.wdc.com/T/#md10b0108b3ccbb1254fe0ad8dbb6e98044a8820b

Please let me know your opinions.

Thanks,
Nitin
-----Original Message-----
From: Christoph Hellwig <hch at infradead.org> 
Sent: Friday, February 11, 2022 11:53 AM
To: Nitin Rawat (QUIC) <quic_nitirawa at quicinc.com>
Cc: Keith Busch <kbusch at kernel.org>; Jens Axboe <axboe at fb.com>; Sagi Grimberg <sagi at grimberg.me>; linux-nvme at lists.infradead.org; linux-kernel at vger.kernel.org; Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu at quicinc.com>
Subject: Re: [PATCH v3] nvme/pci: Add quick suspend quirk for Sc7280 Platform

On Fri, Feb 11, 2022 at 02:23:28AM +0530, Nitin Rawat wrote:
> Enable quick suspend quirks for Sc7280 platform, where power to nvme 
> device is removed during suspend-resume process. This is done to avoid 
> the failure dring resume.

You need to sort this out in the PCI and PM layers.  The broken platform will also affect all other PCIe drivers and not just nvme.