freebsd-skq/share/man/man4/asmc.4

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.Dd April 2, 2019
.Dt ASMC 4
.Os
.Sh NAME
.Nm asmc
.Nd device driver for the Apple System Management Controller (SMC)
.Sh SYNOPSIS
To compile this driver into the kernel, place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device asmc"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
asmc_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver controls the Apple System Management Controller (SMC for short)
found on Intel Apple systems.
.Pp
The SMC is known to be found on the following systems:
.Pp
.Bl -bullet -offset indent -compact
.It
MacBook
.It
MacBook Pro
.It
Intel MacMini
.It
Mac Pro
.It
MacBook Air
.It
Intel iMac
.El
.Pp
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.
.Pp
Variables related to the SMC control and inspection are exported via
.Xr sysctl 3
under the device tree
.Va dev.asmc .
.Sh KEYBOARD BACKLIGHT
On
.Tn MacBook Pro
systems, you can control the keyboard brightness by writing a value to
the
.Va dev.asmc.%d.light.control
sysctl MIB.
.Pp
The following sysctl MIBs contains the raw value returned by the left
and right light sensors:
.Va dev.asmc.%d.light.left
or
.Va dev.asmc.%d.light.right .
.Sh TEMPERATURES
The number of temperature sensors and their description varies among
systems.
You can inspect the temperature sensors on your system by traversing
the
.Va dev.asmc.temp
sysctl MIB.
.Pp
All values are in degrees celsius.
.Sh SYSTEM FANS
The
.Va dev.asmc.fan.%d
sysctl tree contains the leaf nodes
.Va speed ,
.Va safespeed ,
.Va minspeed ,
.Va maxspeed
and
.Va targetspeed .
Each of these leaf nodes represent the current fan speed, the safest
minimum fan speed, the minimum speed and the maximum speed
respectively.
.Pp
All values are in RPM.
.Sh 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
.Va dev.asmc.sms
all relate to the SMS.
.Pp
The most interesting usage of this device is to park the disk heads
when the laptop is moved harshly.
First, you need to install
.Xr ataidle 8 Pq Pa ports/sysutils/ataidle
and then configure
.Xr devd 8
the following way:
.Bd -literal -offset indent
notify 0 {
	match "system"		"ACPI";
	match "subsystem"	"asmc";
	action			"/usr/local/sbin/ataidle -s X Y";
};
.Ed
.Pp
Do not forget to change the
.Ar X
and
.Ar Y
values in the command above.
.Pp
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.
.Sh SEE ALSO
.Xr ataidle 8 Pq Pa ports/sysutils/ataidle ,
.Xr devd 8 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 8.0 .
.Sh AUTHORS
.An Rui Paulo Aq Mt rpaulo@FreeBSD.org
(Google Summer of Code project)
.Sh BUGS
Support for the latest models was never tested and is most likely not
fully working.