> For a7n8x-x fan1_div is surely 4 Depends on the fan itself, not the motherboard. > with fan1_div 2 in /etc/sensors.conf > newdeal:/home/robs# sensors -s > newdeal:/home/robs# sensors > ... > as99127f-i2c-1-2d > ... > fan1: 5000 RPM (min = 2657 RPM, div = 2) > > > with fan1_div 4 in /etc/sensors.conf > newdeal:/home/robs# sensors -s > newdeal:/home/robs# sensors > eeprom-i2c-0-51 > ... > as99127f-i2c-1-2d > ... > fan1: 2463 RPM (min = 1328 RPM, div = 4) > > (second run with no pause and no change in sensors.conf) > newdeal:/home/robs# sensors > ... > as99127f-i2c-1-2d > ... > fan1: 4963 RPM (min = 1328 RPM, div = 4) This is the expected behavior. When you set the divisor, you change a range vs. accuracy setting. You do *not* change the reported value. This might seem strange at first, but that's the way it goes. You might want to read doc/fan-divisors for more information. As you change the divisor from 2 to 4, you say to the chip: "instead of reporting 1 revolution every 2, now report 1 every 4 [1]". But this doesn't change the value stored in the register. You have to wait that the chipset writes a value there again, taking the new fan divisor into account. In your example above, the second time you run sensors, the chipset has been filling the register while divisor was set to 2, but the sensors program sees the divisor at 4, so it computes the value from the register as if the chipset has filled it with divisor 4, thus the bad value. If you want sensors to match your BIOS readings, don't use fan divisors, use the following line in your configuration file instead: compute fan1 @/2, 2*@ [1] Actually, most fans return two pulses for one rotation, thus the default divisor of 2. -- Jean Delvare http://www.ensicaen.ismra.fr/~delvare/
