Re: [PATCH v2 2/3] power: reset: pscrr: add watchdog pretimeout reason tracking

[Matti Vaittinen <mazziesaccount@gmail.com>]

On 22/07/2026 18:13, Faruque Ansari wrote:
> Watchdog pretimeout resets are not recorded with a dedicated reset
> 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 reset 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.c           | 7 ++++++-
>   include/linux/power/power_on_reason.h | 1 +
>   include/linux/reboot.h                | 1 +
>   kernel/reboot.c                       | 1 +
>   4 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/power/reset/pscrr.c b/drivers/power/reset/pscrr.c
> index b5906f127e88..5b107c62fe82 100644
> --- a/drivers/power/reset/pscrr.c
> +++ b/drivers/power/reset/pscrr.c
> @@ -149,7 +149,12 @@ static int pscrr_panic_notifier(struct notifier_block *nb,
>   	if (!backend || !backend->ops || !backend->ops->write_reason)
>   		return NOTIFY_OK;
>   
> -	set_psc_reason(PSCR_KERNEL_PANIC);
> +	/*
> +	 * Do not overwrite a previously recorded watchdog pretimeout reason
> +	 * during panic handling.
> +	 */
> +	if (get_psc_reason() != PSCR_WATCHDOG_PRETIMEOUT)
> +		set_psc_reason(PSCR_KERNEL_PANIC);

Hi Faruque,

I like the idea of adding WDG pretimeout resets in pscrr. I am just 
wondering what makes WDG reason so special, that it shouldn't be 
overwritten while other reasons can be? Can this notifier be called (now 
or in the future) so, that there are other reasons getting overwritten? 
For some reason I think the PSCRR was designed to be able to store 
multiple reasons(?) Could you just add one more instead of overwriting 
existing - or should the check be more generic (to ensure the reason is 
only set if there is nothing to overwrite).

If I am just completely lost (which happens), could you then improve the 
comment a bit to explain why WDG timeout is special and shouldn't be 
overwritten. The checking code itself is quite self-explatonary ;)

Anyways, I am happy to see the PSCRR being worked on! Thanks!

Yours,
  -- Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~