Re: [PATCH v1 0/3] introduce priority-based shutdown support

From: Mark Brown
Date: Sat Nov 25 2023 - 05:31:47 EST


On Sat, Nov 25, 2023 at 09:09:01AM +0000, Greg Kroah-Hartman wrote:
> On Sat, Nov 25, 2023 at 09:50:38AM +0100, Oleksij Rempel wrote:

> > It prevents HW damage. In a typical automotive under-voltage labor it is
> > usually possible to reproduce X amount of bricked eMMCs or NANDs on Y
> > amount of under-voltage cycles (I do not have exact numbers right now).
> > Even if the numbers not so high in the labor tests (sometimes something
> > like one bricked device in a month of tests), the field returns are
> > significant enough to care about software solution for this problem.

> So hardware is attempting to rely on software in order to prevent the
> destruction of that same hardware? Surely hardware designers aren't
> that crazy, right? (rhetorical question, I know...)

Surely software people aren't going to make no effort to integrate with
the notification features that the hardware engineers have so helpfully
provided us with?

> > Same problem was seen not only in automotive devices, but also in
> > industrial or agricultural. With other words, it is important enough to bring
> > some kind of solution mainline.

> But you are not providing a real solution here, only a "I am going to
> attempt to shut down a specific type of device before the others, there
> are no time or ordering guarantees here, so good luck!" solution.

I'm not sure there are great solutions here, the system integrators are
constrained by the what the application appropriate silicon that's on
the market is capable of, the siicon is constrained by the area costs of
dealing with corner cases for system robustness and how much of the
market cares about fixing these issues and software is constrained by
what hardware ends up being built. Everyone's just got to try their
best with the reality they're confronted with, hopefully what's possible
will improve with time.

> And again, how are you going to prevent the in-fighting of all device
> types to be "first" in the list?

It doesn't seem like the most complex integration challenge we've ever
had to deal with TBH.

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