Re: [PATCH v3] thermal/core: Clear all mitigation when thermal zone is disabled

From: Rafael J. Wysocki
Date: Wed Jan 19 2022 - 15:03:32 EST


On Fri, Jan 7, 2022 at 7:57 PM Manaf Meethalavalappu Pallikunhi
<quic_manafm@xxxxxxxxxxx> wrote:
>
> Whenever a thermal zone is in trip violated state, there is a chance
> that the same thermal zone mode can be disabled either via thermal
> core API or via thermal zone sysfs. Once it is disabled, the framework
> bails out any re-evaluation of thermal zone. It leads to a case where
> if it is already in mitigation state, it will stay the same state
> until it is re-enabled.
>
> To avoid above mentioned issue, on thermal zone disable request
> reset thermal zone and clear mitigation for each trip explicitly.
>
> Signed-off-by: Manaf Meethalavalappu Pallikunhi <quic_manafm@xxxxxxxxxxx>
> ---
> drivers/thermal/thermal_core.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 51374f4..e288c82 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -447,10 +447,18 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
>
> thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
>
> - if (mode == THERMAL_DEVICE_ENABLED)
> + if (mode == THERMAL_DEVICE_ENABLED) {
> thermal_notify_tz_enable(tz->id);
> - else
> + } else {
> + int trip;
> +
> + /* make sure all previous throttlings are cleared */
> + thermal_zone_device_init(tz);
> + for (trip = 0; trip < tz->trips; trip++)
> + handle_thermal_trip(tz, trip);
> +

It looks to me like this has a potential of confusing user space by
setting the temperature to invalid before notifying it that the zone
has been disabled.

> thermal_notify_tz_disable(tz->id);
> + }
>
> return ret;
> }
>