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ASMC(4) 		     Kernel Interfaces Manual			 ASMC(4)

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  sys-
     tems.  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 dramati-
     cally 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.

FreeBSD ports 15.1		  April 2, 2019 			 ASMC(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=asmc&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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