Re: [RFC PATCH v1 7/7] thermal: core: set Power State Change Reason before hw_protection_shutdown()

From: Rafael J. Wysocki
Date: Fri Jan 19 2024 - 15:12:18 EST


On Fri, Jan 19, 2024 at 8:34 PM Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote:
>
> On Fri, Jan 19, 2024 at 07:34:26PM +0100, Rafael J. Wysocki wrote:
> > On Fri, Jan 19, 2024 at 2:25 PM Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote:
> > >
> > > Store the state change reason to some black box for later investigation.
> >
> > Seriously?
> >
> > What black box, where, how this is useful and who is going to use it,
> > pretty please.
>
> The 'black box' refers to a non-volatile memory (NVMEM) cell used by the
> Power State Change Reasons (PSCR) framework. This cell stores reasons
> for sudden power state changes, like voltage drops or over-temperature
> events. This data is invaluable for post-mortem analysis to understand
> system failures or abrupt shutdowns. It's particularly useful for
> systems where PMICs or watchdogs cannot record such events. The data can
> inform recovery routines in the bootloader or early kernel stages during
> subsequent boots, enhancing system reliability and aiding in debugging
> and diagnostics.

OK, so please add all of the above to the patch changelog.