Re: [PATCH 1/3] thermal/drivers/intel: Use generic trip points for quark_dts

[Daniel Lezcano]

On 31/01/2023 20:11, Rafael J. Wysocki wrote:
> On Tue, Jan 31, 2023 at 5:41 PM Daniel Lezcano
> <daniel.lezcano@xxxxxxxxxx> wrote:
> > On 26/01/2023 15:15, Rafael J. Wysocki wrote:
> > > On Wed, Jan 18, 2023 at 7:16 PM Daniel Lezcano
> > > <daniel.lezcano@xxxxxxxxxx> wrote:
> > > > The thermal framework gives the possibility to register the trip
> > > > points with the thermal zone. When that is done, no get_trip_* ops are
> > > > needed and they can be removed.
> > > >
> > > > Convert ops content logic into generic trip points and register them with the
> > > > thermal zone.
> > > >
> > > > Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > > > ---
> >
> > [ ... ]
> >
> > > > -       aux_entry->tzone = thermal_zone_device_register("quark_dts",
> > > > -                       QRK_MAX_DTS_TRIPS,
> > > > -                       wr_mask,
> > > > -                       aux_entry, &tzone_ops, NULL, 0, polling_delay);
> > > > +       err = get_trip_temp(QRK_DTS_ID_TP_CRITICAL, &temperature);
> > > > +       if (err)
> > > > +               goto err_ret;
> > > > +
> > > > +       aux_entry->trips[QRK_DTS_ID_TP_CRITICAL].temperature = temperature;
> > > > +       aux_entry->trips[QRK_DTS_ID_TP_CRITICAL].type = THERMAL_TRIP_CRITICAL;
> > > > +
> > > > +       err = get_trip_temp(QRK_DTS_ID_TP_HOT, &temperature);
> > > > +       if (err)
> > > > +               goto err_ret;
> > >
> > > If I'm not mistaken, this won't even try to register the thermal zone
> > > if at least one trip cannot be initialized, but previously it was
> > > registered in that case, but the trips that failed to respond were
> > > disabled.
> > >
> > > This is a change in behavior that would at least need to be documented
> > > in the changelog, but it isn't.
> > >
> > > I'm not sure if it is safe to make even, however.
> >
> > Thanks for catching this.
> >
> > Two solutions:
> >
> > 1. Set the temperature to THERMAL_TEMP_INVALID and change
> > get_thermal_trip() to return -EINVAL or -ERANGE if the temperature is
> > THERMAL_TEMP_INVALID
> >
> > 2. Register only the valid trip points.
> >
> > What would be the preferable way ?
>
> I think that the trip points that are registered currently need to
> still be registered after the change.
>
> Does registering a trip point with the temperature set to
> THERMAL_TEMP_INVALID cause it to be effectively disabled?

No but if we have thermal_zone_get_trip() returning -EINVAL if 
THERMAL_TEMP_INVALID is set for the specified trip id. Then the 
registering will set the disabled flag.

https://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux.git/tree/drivers/thermal/thermal_core.c?h=thermal/bleeding-edge#n1395




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