linux-kernel - Re: Query related to shutting down NVMe during system suspend

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Date:   Thu, 10 Feb 2022 09:41:04 +0530
From:   Vidya Sagar <vidyas@...dia.com>
To:     Keith Busch <kbusch@...nel.org>, <robh+dt@...nel.org>
CC:     <rafael.j.wysocki@...el.com>, <keith.busch@...el.com>,
        <hch@....de>, <bhelgaas@...gle.com>, <mmaddireddy@...dia.com>,
        <kthota@...dia.com>, <sagar.tv@...il.com>,
        <linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: Query related to shutting down NVMe during system suspend



On 2/10/2022 1:56 AM, Keith Busch wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Tue, Feb 01, 2022 at 09:52:28PM +0530, Vidya Sagar wrote:
>> Hi Rafael & Christoph,
>> My query is regarding the comment and the code that follows after it at
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/nvme/host/pci.c?h=v5.17-rc2#n3243
>> What I understood from it is that, there is an underlying assumption
>> that the power to the devices is not removed during the suspend call.
>> In the case of device-tree based platforms like Tegra194, power is
>> indeed removed to the devices during suspend-resume process. Hence, the
>> NVMe devices need to be taken through the shutdown path irrespective of
>> whether the ASPM states are enabled or not.
>> I would like to hear from you the best method to follow to achieve this.
> 
> Christoph prefers to append quirks for platforms that need full device
> shutdown on s2idle instead of changing the driver default.
> 
> We use dmi matching for our current platform quirk list. I do not know
> what the equivalent is for device-tree based platforms. Do you know?
I'm afraid I don't.
Rob, could you please help here?

>