On Wed, Jan 26, 2022 at 04:18:25PM +0200, Vadim Pasternak wrote: > Recently 'cur_state' user space 'sysfs' interface 'sysfs' has been > deprecated. This interface is used in Nvidia systems for setting fan > speed limit. Currently fan speed limit is set from the user space by > setting 'sysfs' 'cur_state' attribute to 'max_state + n', where 'n' is > required limit, for example: 15 for 50% speed limit, 20 for full fan > speed enforcement. > The purpose of this feature is to provides ability to limit fan speed > according to some system wise considerations, like absence of some > replaceable units (PSU or line cards), high system ambient temperature, > unreliable transceivers temperature sensing or some other factors which > indirectly impacts system's airflow. > > The motivation is to support fan low limit feature through 'hwmon' > interface. > > Use 'hwmon' 'pwm' attribute for setting low limit for fan speed in > case 'thermal' subsystem is configured in kernel. In this case setting > fan speed through 'hwmon' will never let the 'thermal' subsystem to > select a lower duty cycle than the duty cycle selected with the 'pwm' > attribute. > From other side, fan speed is to be updated in hardware through 'pwm' > only in case the requested fan speed is above last speed set by > 'thermal' subsystem, otherwise requested fan speed will be just stored > with no PWM update. > > Signed-off-by: Vadim Pasternak <vadimp@xxxxxxxxxx> Applied with minimal change. Guenter ... > + /* Sit minimal PWM speed. */ s/Sit/Set/
