---
name: "acpi_video"
section: "4"
platform: "linux"
package: "freebsd-manpages"
version: "6.0-5"
release: "Debian 4.0 (Etch)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/acpi_video"
---

# acpi\_video(4)

ACPI Video Extensions driver

## 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)](/sysctl/8.md) 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)](/sysctl.conf/5.md), which is parsed at boot-time.

## SEE ALSO

[acpi(4)](/acpi/4.md), [loader.conf(5)](/loader.conf/5.md), [sysctl.conf(5)](/sysctl.conf/5.md), [sysctl(8)](/sysctl/8.md)

## 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)](/acpi_toshiba/4.md)) must be used instead.