Kernel driver `smsc74m1.o' ========================= Status: Beta. Supported chips: * SMSC 74M1xx Super I/O Controllers Addresses scanned: none, address read from Super I/O config space Datasheets: http://www.smsc.com/main/datasheets/47m10x.pdf http://www.smsc.com/main/datasheets/47m120.pdf http://www.smsc.com/main/datasheets/47m13x.pdf http://www.smsc.com/main/datasheets/47m14x.pdf Authors: Mark D. Studebaker With assistance from Bruce Allen and his fan.c program: http://www.lsc-group.phys.uwm.edu/%7Eballen/driver/ Module Parameters ----------------- force_addr=0xaddr Set the I/O base address. Useful for boards that don't set the address in the BIOS. Don't use this unless the driver complains that the base address is not set. Example: 'modprobe smsc47m1 force_addr=0x680' Description ----------- The Standard Microsystems Corporation (SMSC) 47M1xx Super I/O chips contain monitoring and PWM control circuitry for two fans. FAN rotation speeds are reported in RPM (rotations per minute). An alarm is triggered if the rotation speed has dropped below a programmable limit. FAN readings can be divided by a programmable divider (1, 2, 4 or 8) to give the readings more range or accuracy. This is important because some FANs report only one 'tick' each rotation, while others report two - making all readings twice as high. Not all RPM values can accurately be represented, so some rounding is done. With a divider of 2, the lowest representable value is around 2600 RPM. PWM values are from 0 to 255. The first value in the /proc entry is the pwm value; the second is the enable (0 or 1). If an alarm triggers, it will remain triggered until the hardware register is read at least once. This means that the cause for the alarm may already have disappeared! Note that in the current implementation, all hardware registers are read whenever any data is read (unless it is less than 1.5 seconds since the last update). This means that you can easily miss once-only alarms. ********************** The lm_sensors project gratefully acknowledges the support of Intel in the development of this driver.