NAME

       asmc — device driver for the Apple System Management Controller (SMC)

SYNOPSIS

       To compile this driver into the kernel, place the following line in your kernel configuration file:

             device asmc

       Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

             asmc_load="YES"

DESCRIPTION

       The  asmc  driver  controls  the  Apple System Management Controller (SMC for short) found on Intel Apple
       systems.

       The SMC is known to be found on the following systems:

             •   MacBook
             •   MacBook Pro
             •   Intel MacMini
             •   Mac Pro
             •   MacBook Air
             •   Intel iMac

       With this driver, you can configure your keyboard backlight brightness,  check  temperatures  of  several
       sensors, check the speed of the internal fans and check the status of the Sudden Motion Sensor.

       Variables  related  to  the  SMC  control and inspection are exported via sysctl(3) under the device tree
       dev.asmc.

KEYBOARD BACKLIGHT

       On  MacBook  Pro  systems,  you  can  control  the  keyboard  brightness  by  writing  a  value  to   the
       dev.asmc.%d.light.control sysctl MIB.

       The  following  sysctl  MIBs  contains  the  raw  value  returned  by  the  left and right light sensors:
       dev.asmc.%d.light.left or dev.asmc.%d.light.right.

TEMPERATURES

       The number of temperature sensors and their description  varies  among  systems.   You  can  inspect  the
       temperature sensors on your system by traversing the dev.asmc.temp sysctl MIB.

       All values are in degrees celsius.

SYSTEM FANS

       The  dev.asmc.fan.%d  sysctl  tree  contains  the  leaf  nodes  speed,  safespeed, minspeed, maxspeed and
       targetspeed.  Each of these leaf nodes represent the current fan speed, the safest minimum fan speed, the
       minimum speed and the maximum speed respectively.

       All values are in RPM.

SUDDEN MOTION SENSOR

       The Sudden Motion Sensor (SMS for short) is a device  that  detects  laptop  movement  and  notifies  the
       operating system via an interrupt.  The sysctl MIBs present under dev.asmc.sms all relate to the SMS.

       The  most  interesting  usage  of this device is to park the disk heads when the laptop is moved harshly.
       First, you need to install ataidle(8) (ports/sysutils/ataidle) and then configure devd(8)  the  following
       way:

             notify 0 {
                     match "system"          "ACPI";
                     match "subsystem"       "asmc";
                     action                  "/usr/local/sbin/ataidle -s X Y";
             };

       Do not forget to change the X and Y values in the command above.

       Also,  please  note  that parking the disk heads too many times can dramatically reduce your hard drive's
       life span.  Do not rely solely on the SMS to protect your hard drive: good  care  and  common  sense  can
       increase your hard drive's life.

SEE ALSO

       ataidle(8) (ports/sysutils/ataidle), devd(8), sysctl(8)

HISTORY

       The asmc driver first appeared in FreeBSD 8.0.

AUTHORS

       Rui Paulo <rpaulo@FreeBSD.org> (Google Summer of Code project)

BUGS

       Support for the latest models was never tested and is most likely not fully working.

Debian                                            April 2, 2019                                          ASMC(4)