Re: [PATCH v3] hwmon: (cros_ec) Add set and get target fan RPM function

[Guenter Roeck]

On 3/25/25 00:16, Sung-Chi Li wrote:

> Currently, when sending the fan control setting to EC, EC will switch to manual
> fan control automatically. When system suspends or shuts down, fans are going
> back to automatic control (based on current EC implementation).
>
> Do you mean the driver should not change the fan control method if there is no
> pwmY_enable implemented, or it is the user that should first explicitly set the
> fan to manualy mode, then the user can specify the desired fan speed?

The user should first set the fan control method to manual mode.

Unless I am missing something, setting manual mode means that pwmY_enable does have
to be implemented.

Note that the suspend/resume behavior is unexpected. The user would assume that the fan
control method is still in the same mode after resume. If resume reverts to automatic mode,
there should be a suspend/resume handler which restores the mode on resume.

Thanks,
Guenter