ACPI_VIDEO(4)          FreeBSD Kernel Interfaces Manual          ACPI_VIDEO(4)

NAME
     acpi_video - ACPI Video Extensions driver

SYNOPSIS
     device acpi_video

DESCRIPTION
     This driver uses the ACPI Video Extensions to control display switching
     and backlight brightness.  The availability of the sysctl(8) variables
     depends on the functions offered by the host's ACPI implementation.

SYSCTL VARIABLES
     The following sysctls are currently implemented, where <device> is crt,
     lcd, or tv:

     hw.acpi.video.<device>.active
             Current state of the output device.

     hw.acpi.video.<device>.levels
             List of supported brightness levels.

     hw.acpi.video.<device>.brightness
             Current brightness level of the device.

     hw.acpi.video.<device>.fullpower
             Preset brightness level to be used in full power mode.

     hw.acpi.video.<device>.economy
             Preset brightness level to be used in economy mode.

     Defaults for these variables can be set in sysctl.conf(5), which is
     parsed at boot-time.

COMPATIBILITY
     In order for acpi_video to attach correctly, acpi_video should be loaded
     after any of the DRM kernel modules.  This can be achieved by setting the
     correct order in rc.conf(5) using the kld_list directive.

SEE ALSO
     acpi(4), loader.conf(5), sysctl.conf(5), sysctl(8)

HISTORY
     The acpi_video driver first appeared in FreeBSD 5.3.

AUTHORS
     The acpi_video driver was written by Taku YAMAMOTO
     <taku@cent.saitama-u.ac.jp>.  This manual page was written by Mark
     Santcroos <marks@ripe.net>.

BUGS
     Some systems only perform output switching via SMM even though they
     export the proper information via ACPI.  On such systems, the proper
     hotkeys or OEM driver (for example, acpi_toshiba(4)) must be used
     instead.

FreeBSD 13.1-RELEASE-p6        November 8, 2004        FreeBSD 13.1-RELEASE-p6