Re: Query related to shutting down NVMe during system suspend

[nitirawa]

On 2022-02-01 22:28, Vidya Sagar wrote:
> Thanks for the super quick reply and I couldn't agree more.
>
> On 2/1/2022 10:00 PM, 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.
> >
> > Since platform makers can't converge on how to let a driver know what
> > it's supposed to do, I suggest we default to the simple shutdown 
> > suspend
> > all the time. We can add a module parameter to let a user request nvme
> > power management if they really want it. No matter what we do here,
> > someone is going to complain, but at least simple shutdown is safe...

Hi Vidya,

Are you planning to add module parameter based on above discussion. I 
see similar behaviour even with  qualcomm platform.

[  119.994092] nvme nvme0: I/O 9 QID 0 timeout, reset controller
[  120.006612] PM: dpm_run_callback(): pci_pm_resume+0x0/0xe4 returns 
-16
[  120.013502] nvme 0001:01:00.0: PM: pci_pm_resume+0x0/0xe4 returned 
-16 after 60059958 usecs
[  120.022239] nvme 0001:01:00.0: PM: failed to resume async: error -16

Regards,
Nitin