Re: [PATCH v2] hwmon: (coretemp) Return -ENODATA for invalid temperature readings

[sashiko-bot@kernel.org]

> IA32_THERM_STATUS and IA32_PACKAGE_THERM_STATUS have a valid bit, bit 31.
> The Intel SDM documents it only for the former, but the package register
> implements it too: x86_pkg_temp_thermal has required it since commit
> f1a18a105660 ("Thermal: CPU Package temperature thermal").
> 
> This driver checked the bit for both registers as well, until
> commit bf6ea084ebb5 ("hwmon: (coretemp) Do not return -EAGAIN for low
> temperatures") made it ignore the bit because some CPUs clear it while
> the temperature is too low to be measured. Since then, temp%d_input
> reports such a reading as a real temperature. Userspace cannot tell it
> apart from a genuinely low one.
> 
> Fail the read with -ENODATA while the CPU reports the reading as invalid.
> On a CPU that clears the bit, reading temp%d_input now fails where it
> used to return a low value. sensors(1) shows N/A in its place.
> 
> Suggested-by: Guenter Roeck <linux@roeck-us.net>
> Link: https://lore.kernel.org/all/46f9f319-de71-412f-a424-6cb801478456@roeck-us.net/
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261006-coretemp-enodata-v2-1-64e788acc7dc@linux.intel.com?part=1