Re: Query related to shutting down NVMe during system suspend

[Rafael J. Wysocki]

On Tuesday, February 1, 2022 5:30:54 PM CET Keith Busch wrote:
> 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...

Agreed.