asmctl

Apple System Management Controller

Asmctl is a command line tool for Apple System Management Controller, which controls keyboard backlight and LCD backlight.

LCD backlight

The asmctl command tries to use backlight(9) device at first. If it's not available, use "hw.acpi.video.lcd0.*" sysctl value instead. The backlight(9) driver is introduced by FreeBSD 13.0. The backlight(9) overrides ACPI sysctl configuration while it's working. The asmctl command will open the '/dev/backlight/backlight0' device file to see if the backlight(9) device is available.

Keyboard backlight

The asmctl uses "dev.asmc.0.*" sysctl values to configure the keyboard backlight.

REQUIREMENTS

Asmctl requires the following two kernel modules.

1. asmc
2. acpi_video

To load these modules on boot, write following lines in /boot/loader.conf.

asmc_load="YES"
acpi_video_load="YES"

HOW TO INSTALL

$ ./configure
$ make
$ make install

HOW TO USE

1. Brighten the LCD backlight

   $ /usr/local/bin/asmctl video up
   

2. Dim the LCD backlight

   $ /usr/local/bin/asmctl video down
   

3. Brighten the keyboard backlight

   $ /usr/local/bin/asmctl key up
   

4. Dim the keyboard backlight

   $ /usr/local/bin/asmctl key down
   

Assigning following key bindings work similar to Apple Macbook series.

key	assign
F1	asmctl video down
F2	asmctl video up
F5	asmctl key down
F6	asmctl key up

FOLLOWING AC POWER STATUS

FreeBSD kernel has two acpi video brightness values. One is for ac powered and the other is for battery powered.

Asmctl adjusts these two values relies on acpi ac power status.

/usr/local/etc/devd/asmctl.conf makes FreeBSD devd triggering asmctl video acpi and asmctl key acpi.

SECURITY

Changing hw.acpi.video.* sysctl variables requires root privilege. For this reason, asmctl is installed with setuid root. On FreeBSD-11.0R or higher, asmctl uses capsicum(4) to be sandboxed.