Re: [PATCH v14 4/6] reboot: extend psc_reason with power-on and reset causes

[Faruque Ansari]

Hi Matti Vaittinen,

On 22-Sep-26 1:15 PM, Matti Vaittinen wrote:
> On 21/09/2026 20:44, Faruque Ansari wrote:
> > psc_reason covered only the protection reasons. Extend it to 
> > mirror the
> > full POWER_ON_REASON_* vocabulary - power-on, watchdog, software,
> > external, RTC, reset button, CPU clock and crystal failures - so a
> > provider can report why the system last powered on, not only 
> > why it was
> > shut down. New values are appended to keep the existing numeric 
> > ABI.
> >
> > Co-developed-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> > Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> > Signed-off-by: Faruque Ansari <faruque.ansari@xxxxxxxxxxxxxxxx>
> >
> > changes v12:
> > - new patch
> > ---
> >   include/linux/reboot.h | 28 ++++++++++++++++++++++++++++
> >   kernel/reboot.c        |  8 ++++++++
> >   2 files changed, 36 insertions(+)
> >
> > diff --git a/include/linux/reboot.h b/include/linux/reboot.h
> > index 4c5327dd7645..13f004ad1066 100644
> > --- a/include/linux/reboot.h
> > +++ b/include/linux/reboot.h
> > @@ -225,9 +225,28 @@ extern void orderly_reboot(void);
> >    *    management errors, or an unrecoverable hardware fault 
> > requiring
> >    *    immediate response.
> >    *
> > + * @PSCR_POWER_ON: Regular cold power-on (e.g. via a PMIC 
> > power-on request).
> > + *
> > + * @PSCR_WATCHDOG: Reset caused by a watchdog timeout.
> > + *
> > + * @PSCR_SOFTWARE: Software-initiated reset or reboot.
> > + *
> > + * @PSCR_EXTERNAL: Reset asserted through an external pin or 
> > reset input.
> > + *
> > + * @PSCR_RTC: Wake-up or power-on triggered by the RTC.
> > + *
> > + * @PSCR_RESET_BUTTON: Reset triggered by a user reset button.
> > + *
> > + * @PSCR_CPU_CLK_FAIL: Reset caused by a CPU clock failure.
> > + *
> > + * @PSCR_XTAL_FAIL: Reset caused by a crystal oscillator failure.
> > + *
> >    * @PSCR_REASON_COUNT: Number of defined power state change 
> > reasons. This
> >    *    value is useful for range checking and potential future 
> > extensions
> >    *    while maintaining compatibility.
> > + *
> > + * The reasons mirror the POWER_ON_REASON_* strings in
> > + * <linux/power/power_on_reason.h>; keep the two in sync when 
> > extending.
>
> (still a nit)
> We should now also ensure the psc_reason_desc[] in reboot.c stays 
> in sync... (See my nits for 3/6). I have a nagging feeling this 
> is not optimal :)

Thanks for the review.
I will address this in patch 3/6.

> Is there a reason for having this as a separate patch and not 
> merged with 3/6? If yes:
Yes, there is a reason.
patch 3/6 introduces the mechanism — the struct, the token/label 
table shape, and the two accessor functions.
patch 4/6 only adds data on top of that — new enum values and 
their matching table rows, nothing else.
Keeping them separate keeps each patch focused on a single 
concern and makes review, bisection, and potential reverts more 
straightforward.

Thanks,
Faruque Ansari

> Reviewed-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
>
> >    */
> >   enum psc_reason {
> >       PSCR_UNKNOWN,
> > @@ -236,6 +255,15 @@ enum psc_reason {
> >       PSCR_REGULATOR_FAILURE,
> >       PSCR_OVER_TEMPERATURE,
> >       PSCR_EC_PANIC,
> > +    /* Append new reasons here; the numeric order is ABI. */
> > +    PSCR_POWER_ON,
> > +    PSCR_WATCHDOG,
> > +    PSCR_SOFTWARE,
> > +    PSCR_EXTERNAL,
> > +    PSCR_RTC,
> > +    PSCR_RESET_BUTTON,
> > +    PSCR_CPU_CLK_FAIL,
> > +    PSCR_XTAL_FAIL,
> >       /* Number of reasons */
> >       PSCR_REASON_COUNT,
> > diff --git a/kernel/reboot.c b/kernel/reboot.c
> > index e53fb31bad06..5d4ecc82b35e 100644
> > --- a/kernel/reboot.c
> > +++ b/kernel/reboot.c
> > @@ -1102,6 +1102,14 @@ static const struct psc_reason_desc 
> > psc_reason_descs[] = {
> >       [PSCR_REGULATOR_FAILURE] = { "regulator-failure", 
> > POWER_ON_REASON_REGULATOR_FAILURE },
> >       [PSCR_OVER_TEMPERATURE]     = { "over-temperature",  
> > POWER_ON_REASON_OVER_TEMPERATURE },
> >       [PSCR_EC_PANIC]         = { "ec-panic",      
> > POWER_ON_REASON_EC_PANIC },
> > +    [PSCR_POWER_ON]         = { "power-on",      
> > POWER_ON_REASON_REGULAR },
> > +    [PSCR_WATCHDOG]         = { "watchdog",      
> > POWER_ON_REASON_WATCHDOG },
> > +    [PSCR_SOFTWARE]         = { "software",      
> > POWER_ON_REASON_SOFTWARE },
> > +    [PSCR_EXTERNAL]         = { "external",      
> > POWER_ON_REASON_EXTERNAL },
> > +    [PSCR_RTC]         = { "rtc",          POWER_ON_REASON_RTC },
> > +    [PSCR_RESET_BUTTON]     = { "reset-button",      
> > POWER_ON_REASON_RST_BTN },
> > +    [PSCR_CPU_CLK_FAIL]     = { "cpu-clock-failure", 
> > POWER_ON_REASON_CPU_CLK_FAIL },
> > +    [PSCR_XTAL_FAIL]     = { "crystal-failure",      
> > POWER_ON_REASON_XTAL_FAIL },
> >   };
> >   /**