Re: [PATCH v2 1/2] PM: enable support for imminent power loss

[Keith Busch]

On Mon, Jul 26, 2021 at 09:41:46PM +0200, Pavel Machek wrote:
> > If the shutdown is pwerformed when the platform is running on the
> > limited backup power supply, some of the devices might not have enough
> > power to perform a clean shutdown.
> > 
> > It is necessary to inform the driver about the limited backup power
> > supply, to allow the driver to decide to perform the minimal required
> > operation for a fast and clean shutdown.
> 
> If you can do shutdown that is fast & clean, why not do it always?

At least for nvme, I don't think this faster shutdown qualifies as
"clean". It's just a little better than removing power without telling
the device. Typical implementations take longer to become ready on their
next power-on following the abrupt shutdown sequence.