Re: [PATCH] hwmon: (cros_ec): Hide unconfigured temperature thresholds

On 7/28/26 09:38, Daniel Schaefer via B4 Relay wrote:
> From: Daniel Schaefer <[email protected]>
> 
> The EC reports a threshold of 0 K for host thresholds that are not
> configured. Most Framework Computer systems don't use all thresholds.
> E.g. temp_host_warn is left unset and stays at its -273 C / 0 K
> default), see the EC code in zephyr/shim/src/thermal.c:
> 
>    DT_PROP_OR(node_id, temp_host_warn,  -273)
> 
> Previously these unconfigured thresholds were exposed as sysfs limits
> that read back as -273.15 C, which userspace (e.g. s-tui) interpreted as
> a real, permanently-exceeded limit.
> 
> To avoid this we can hide the sysfs attribute for that threshold.
> See truncated example below.
> 

Is the limit just not configured or indeed unsupported ?

If it is indeed unsupported, this is ok. If it is supported but not set
(and it is configurable), this is not ok and will require a better solution.

Guenter

> Before:
> 
>> sensors cros_ec-isa-000c
> cpu_f75303@4d:       +36.9°C  (crit = +74.8°C, emerg = +84.8°C)
> 
> After:
> 
>> sensors cros_ec-isa-000c
> cpu_f75303@4d:       +36.9°C  (high = -273.1°C, crit = +74.8°C)
>                                (emerg = +84.8°C)
> 
> Cc: Tzung-Bi Shih <[email protected]>
> Cc: Thomas Weißschuh <[email protected]>
> Cc: [email protected]
> Signed-off-by: Daniel Schaefer <[email protected]>
> ---
>   drivers/hwmon/cros_ec_hwmon.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
> index 03bfcc40bb7c..57158443dafe 100644
> --- a/drivers/hwmon/cros_ec_hwmon.c
> +++ b/drivers/hwmon/cros_ec_hwmon.c
> @@ -319,6 +319,7 @@ static umode_t cros_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_type
>   					u32 attr, int channel)
>   {
>   	const struct cros_ec_hwmon_priv *priv = data;
> +	u32 threshold;
>   	u16 speed;
>   
>   	if (type == hwmon_fan) {
> @@ -334,8 +335,17 @@ static umode_t cros_ec_hwmon_is_visible(const void *data, enum hwmon_sensor_type
>   	} else if (type == hwmon_temp) {
>   		if (priv->temp_sensor_names[channel]) {
>   			if (cros_ec_hwmon_attr_is_temp_threshold(attr)) {
> -				if (priv->temp_threshold_supported)
> -					return 0444;
> +				if (!priv->temp_threshold_supported)
> +					return 0;
> +
> +				if (cros_ec_hwmon_read_temp_threshold(priv->cros_ec, channel,
> +								      cros_ec_hwmon_attr_to_thres(attr),
> +								      &threshold) != 0)
> +					return 0;
> +				if (threshold == 0)
> +					return 0;
> +
> +				return 0444;
>   			} else {
>   				return 0444;
>   			}
> 
> ---
> base-commit: 58717b2a1365d06c8c64b72aa948541b53fe31eb
> change-id: 20260729-crosec-hwmon-warn-default-9f3ca86ed809
> 
> Best regards,