Re: [PATCH] hwmon: (gpio-fan) Update the speed cache before dropping the PM reference

[sashiko-bot@kernel.org]

> set_fan_speed() writes the GPIO control value before dropping the runtime
> PM reference when stopping the fan. pm_runtime_put_sync() decrements the
> usage count even when suspending the device fails, but the error return
> currently leaves speed_index at the previous running speed.
> 
> A request for that same running speed then returns success without
> changing the GPIOs or taking a runtime PM reference. Retrying the stop
> instead drops a reference the driver no longer owns and can trigger a
> runtime PM usage count underflow warning.
> 
> Update speed_index after writing the GPIOs and before dropping the PM
> reference. The initial same-speed check already excludes a stopped fan,
> so a zero target is sufficient to identify the transition that needs a
> PM put. Preserve the PM error return and the CONFIG_PM=n exception.
> 
> This keeps the cached control state and PM reference ownership consistent
> without restoring running GPIOs after a possibly partial supply failure.
> It does not clear persistent runtime PM errors or claim that a failing
> regulator has successfully powered off.
> 
> Fixes: 0d01110e6356 ("hwmon: (gpio-fan) Add regulator support")
> 
> Signed-off-by: Baek Kyu, Kim <pocj8ur4in@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261031095039.11683-1-pocj8ur4in@gmail.com?part=1