freebsd man page for acpi_video

ACPI_VIDEO(4)						   BSD 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) vari-
     ables 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.

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.

BSD
								 November 8, 2004							       BSD