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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
       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  lap-
       top  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 fol-
       lowing 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  dra-
       matically  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  in-
       crease 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	14.3			 April 2, 2019			       ASMC(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=asmc&sektion=4&manpath=FreeBSD+14.3-RELEASE+and+Ports>

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