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ACPI_VIDEO(4)		     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.

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 7.4			November 8, 2004		   ACPI_VIDEO(4)

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