This patch adds new function i8k_get_fan_nominal_speed() for doing SMM call
which will return nominal fan RPM for specified fan speed. It returns nominal
RPM value at which fan operate when speed (0, 1, 2, 3) is set. It looks like
RPM value is not accurate, but still provides very useful information.
First it can be used to validate if certain fan speed could be accepted by SMM
for setting fan speed and we can use this routine to detect maximal fan speed.
Second it returns RPM value, so we can check if value looks correct with
multiplier 30 or multiplier 1 (until now only these two multiplier were used).
If RPM value with multiplier 30 is too high, then multiplier 1 is used.
In case when SMM reports that new function is not supported we will fallback
to old hardcoded values. Maximal fan speed would be 2 and RPM multiplier 30.
Signed-off-by: Pali RohÃr <pali.rohar@xxxxxxxxx>
Tested-by: Pali RohÃr <pali.rohar@xxxxxxxxx>