Re: [RFC PATCH v1 0/7] Introduction of PSCR Framework and Related Components

[Sebastian Reichel]

Hi,

On Fri, Jan 19, 2024 at 02:25:14PM +0100, Oleksij Rempel wrote:
> This patch series introduces the Power State Change Reasons (PSCR)
> tracking framework and its related components into the kernel. The PSCR
> framework is designed for systems where traditional methods of storing
> power state change reasons, like PMICs or watchdogs, are inadequate. It
> provides a structured way to store reasons for system shutdowns and
> reboots, such as under-voltage or software-triggered events, in
> non-volatile hardware storage.
> 
> These changes are critical for systems requiring detailed postmortem
> analysis and where immediate power-down scenarios limit traditional
> storage options. The framework also assists bootloaders and early-stage
> system components in making informed recovery decisions.

A couple of things come to my mind:

1. Do we need the DT based reason-string-to-integer mapping? Can we
   just use a fixed mapping instead? It simplifies the binding a
   lot. With that the generic part could be dropped completely.

2. I would expect the infrastructure to read and clear the reason
   during boot. If e.g. a watchdog triggers a reset you will otherwise
   get an incorrect value.

3. The reason is only stored, but not used? We have a sysfs ABI to
   expose the reboot reason to userspace since half a year ago, see
   d40befed9a58 (power: reset: at91-reset: add sysfs interface to
   the power on reason).

4. Available options should be synced with the list in
   include/linux/power/power_on_reason.h

-- Sebastian

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