AIBS(4)                 NetBSD Kernel Interfaces Manual                AIBS(4)

     aibs -- ASUSTeK AI Booster voltage, temperature, and fan sensor

     aibs* at acpi?

     The aibs driver provides support for voltage, temperature, and fan sen-
     sors available as an ACPI device on ASUSTeK motherboards.  The number of
     sensors of each type, as well as the description of each sensor, varies
     according to the motherboard.

     The driver supports an arbitrary set of sensors, provides descriptions
     regarding what each sensor is used for, and reports whether each sensor
     is within the specifications as defined by the motherboard manufacturer
     through ACPI.

     The aibs driver supports envsys(4) sensor states as follows:

        Voltage sensors can have a state of `valid', `critunder', or
         `critover'; temperature sensors can have a state of `valid',
         `warnover', `critover', or `invalid'; and fan sensors can have a
         state of `valid', `warnunder', or `warnover'.

        Temperature sensors that have a reading of 0 are marked `invalid',
         whereas all other sensors are always assumed valid.

        Voltage sensors have a lower and an upper limit, `critunder' and
         `critover', temperature sensors have two upper limits, `warnover' and
         `critover', whereas fan sensors may either have only the lower limit
         `warnunder', or, depending on the vendor's ACPI implementation, one
         lower and one upper limit, `warnunder' and `warnover'.

     Sensor values and limits are made available through the envsys(4) inter-
     face, and can be monitored with envstat(8).  For example, on an ASUS
     V3-P5G965 barebone:

       $ envstat -d aibs0
                            Current  CritMax  WarnMax  WarnMin  CritMin Unit
           Vcore Voltage:     1.152    1.600                      0.850    V
            +3.3 Voltage:     3.312    3.630                      2.970    V
              +5 Voltage:     5.017    5.500                      4.500    V
             +12 Voltage:    12.302   13.800                     10.200    V
         CPU Temperature:    27.000   95.000   80.000                   degC
          MB Temperature:    58.000   95.000   60.000                   degC
           CPU FAN Speed:       878              7200      600           RPM
       CHASSIS FAN Speed:         0              7200      700           RPM

     Generally, sensors provided by the aibs driver may also be supported by a
     variety of other drivers, such as lm(4) or itesio(4).  The precise col-
     lection of aibs sensors is comprised of the sensors specifically utilised
     in the motherboard design, which may be supported through a combination
     of one or more physical hardware monitoring chips.

     The aibs driver, however, provides the following advantages when compared
     to the native hardware monitoring drivers:

        Sensor values from aibs are expected to be more reliable.  For exam-
         ple, voltage sensors in many hardware monitoring chips can only sense
         voltage from 0 to 2 or 4 volts, and the excessive voltage is removed
         by the resistors, which may vary with the motherboard and with the
         voltage that is being sensed.  In aibs, the required resistor factors
         are provided by the motherboard manufacturer through ACPI; in the
         native drivers, the resistor factors are encoded into the driver
         based on the chip manufacturer's recommendations.  In essence, sensor
         values from aibs are very likely to be identical to the readings from
         the Hardware Monitor screen in the BIOS.

        Sensor descriptions from aibs are more likely to match the markings
         on the motherboard.

        Sensor states are supported by aibs.  The state is reported based on
         the acceptable range of values for each individual sensor as sug-
         gested by the motherboard manufacturer.  For example, the threshold
         for the CPU temperature sensor is likely to be significantly higher
         than that for the chassis temperature sensor.

        Support for newer chips in aibs.  Newer chips may miss a native
         driver, but should be supported through aibs regardless.

     As a result, sensor readings from the actual native hardware monitoring
     drivers are redundant when aibs is present, and may be ignored as appro-
     priate.  Whereas on some supported operating systems the native drivers
     may have to be specifically disabled should their presence be judged
     unnecessary, on others the drivers like lm(4) are not probed provided
     that acpi(4) is configured and the system potentially supports the hard-
     ware monitoring chip through ACPI.

     acpi(4), envsys(4), envstat(8)

     The aibs driver first appeared in OpenBSD 4.7, DragonFly 2.4.1 and
     NetBSD 6.0.  An earlier version of the driver, named aiboost, first
     appeared in FreeBSD 7.0 and NetBSD 5.0.

     The aibs driver was written for OpenBSD, DragonFly BSD, and NetBSD by
     Constantine A. Murenin <>, Raouf Boutaba Research Group,
     David R. Cheriton School of Computer Science, University of Waterloo.
     Jukka Ruohonen <> later reworked and adjusted the driver
     to support new ASUSTeK motherboards.  The earlier version of the driver,
     aiboost, was written for FreeBSD by Takanori Watanabe and adapted to
     NetBSD by Juan Romero Pardines.

NetBSD 6.0                       June 12, 2011                      NetBSD 6.0

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