Re: [PATCH v4 2/3] power: reset: pscrr: add watchdog pretimeout reason tracking

[Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>]

On 8/5/26 10:54, Faruque Ansari wrote:
> Watchdog pretimeout resets are not recorded with a dedicated reason,
> causing subsequent boots to report PSCR_UNKNOWN and making it difficult
> to distinguish them from other unexpected resets.
> 
> Add PSCR_WATCHDOG_PRETIMEOUT as a dedicated reason code and prevent the
> panic notifier from overwriting a watchdog pretimeout reason with
> PSCR_KERNEL_PANIC when the pretimeout governor triggers a panic.
> 
> Signed-off-by: Faruque Ansari <faruque.ansari@oss.qualcomm.com>
> ---
>   drivers/power/reset/pscrr/pscrr.c     | 11 +++++++----
>   include/linux/power/power_on_reason.h |  1 +
>   include/linux/reboot.h                |  4 ++++
>   kernel/reboot.c                       |  1 +
>   4 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/power/reset/pscrr/pscrr.c b/drivers/power/reset/pscrr/pscrr.c
> index 8c45b84059a9..b7e6239e207e 100644
> --- a/drivers/power/reset/pscrr/pscrr.c
> +++ b/drivers/power/reset/pscrr/pscrr.c
> @@ -529,12 +529,15 @@ static struct notifier_block pscrr_reboot_nb = {
>   static int pscrr_panic_notifier(struct notifier_block *nb,
>   				unsigned long action, void *unused)
>   {
> -	struct pscrr_provider_dir *dir;
>   
> -	set_psc_reason(PSCR_KERNEL_PANIC);
> +	/*
> +	 * Do not overwrite a watchdog pretimeout reason already set by the
> +	 * pretimeout path before it triggered this panic.
> +	 */
> +	if (get_psc_reason() != PSCR_WATCHDOG_PRETIMEOUT)
> +		set_psc_reason(PSCR_KERNEL_PANIC);

It does not sounds correct.

May be you should move the set_psc_reason() to different places for panic.

I did not explore the panic() function but I would suggest to have 
something like:

panic(..., ) --> defaults to PSCR_KERNEL_PANIC

panic_with_pscrr(..., reason)

Then pscrr_panic_notifier() only does the record

> -	list_for_each_entry(dir, &pscrr_dirs, node)
> -		pscrr_do_record(dir, get_psc_reason());
> +	pscrr_record_current();
>   
>   	return NOTIFY_DONE;
>   }
> diff --git a/include/linux/power/power_on_reason.h b/include/linux/power/power_on_reason.h
> index 8c99bdd75021..8e3889fa43ef 100644
> --- a/include/linux/power/power_on_reason.h
> +++ b/include/linux/power/power_on_reason.h
> @@ -21,5 +21,6 @@
>   #define POWER_ON_REASON_EC_PANIC "EC panic"
>   #define POWER_ON_REASON_EXTERNAL "external reset"
>   #define POWER_ON_REASON_KERNEL_PANIC "kernel panic"
> +#define POWER_ON_REASON_WATCHDOG_PRETIMEOUT "watchdog pretimeout"
>   
>   #endif /* POWER_ON_REASON_H */
> diff --git a/include/linux/reboot.h b/include/linux/reboot.h
> index a117dd5eaecd..6d5ecc6cdc00 100644
> --- a/include/linux/reboot.h
> +++ b/include/linux/reboot.h
> @@ -243,6 +243,9 @@ extern void orderly_reboot(void);
>    *
>    * @PSCR_KERNEL_PANIC: Reset that followed a kernel panic.
>    *
> + * @PSCR_WATCHDOG_PRETIMEOUT: Recorded when a watchdog pretimeout fires, before
> + *  the pretimeout governor brings the system down.
> + *
>    * @PSCR_REASON_COUNT: Number of defined power state change reasons. This
>    *	value is useful for range checking and potential future extensions
>    *	while maintaining compatibility.
> @@ -267,6 +270,7 @@ enum psc_reason {
>   	PSCR_CPU_CLK_FAIL,
>   	PSCR_XTAL_FAIL,
>   	PSCR_KERNEL_PANIC,
> +	PSCR_WATCHDOG_PRETIMEOUT,
>   
>   	/* Number of reasons */
>   	PSCR_REASON_COUNT,
> diff --git a/kernel/reboot.c b/kernel/reboot.c
> index 979ecf3b093c..fad4ef9681a6 100644
> --- a/kernel/reboot.c
> +++ b/kernel/reboot.c
> @@ -1110,6 +1110,7 @@ static const struct psc_reason_desc psc_reason_descs[] = {
>   	[PSCR_CPU_CLK_FAIL]	 = { "cpu-clock-failure", POWER_ON_REASON_CPU_CLK_FAIL },
>   	[PSCR_XTAL_FAIL]	 = { "crystal-failure",	  POWER_ON_REASON_XTAL_FAIL },
>   	[PSCR_KERNEL_PANIC]	 = { "kernel-panic",	  POWER_ON_REASON_KERNEL_PANIC },
> +	[PSCR_WATCHDOG_PRETIMEOUT] = { "watchdog-pretimeout", POWER_ON_REASON_WATCHDOG_PRETIMEOUT },
>   };
>   
>   /**
>