acpi_video(4) [debian man page]

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

ACPIVGA(4)						   BSD Kernel Interfaces Manual 						ACPIVGA(4)

NAME

     acpivga -- ACPI Display Adapter and Output Devices

SYNOPSIS

     acpivga* at acpi?
     acpiout* at acpivga?

DESCRIPTION

     The acpivga driver provides generic support for brightness control and output switching, through ACPI video extensions.  The ACPI specifica-
     tion requires that systems containing a built-in display adapter implement these extensions in their ACPI BIOS.

     The driver handles brightness hotkeys and display switch hotkeys.	In addition, the following sysctl(8) read/write variables are provided
     (when hardware support is available):

     hw.acpi.acpivga0.bios_switch
	     BIOS output switching policy.  This boolean variable controls the behavior of the BIOS when a display switch hotkey is pressed.
	     1	  the BIOS should automatically switch outputs, with no interaction from acpivga.
	     0	  the BIOS should only notify acpivga of the desired output state changes.

     hw.acpi.acpiout0.brightness
	     Brightness level.	This integer variable typically ranges from 0 to 100, but any integer value is accepted (the driver uses the clos-
	     est brightness level supported by the device).

     Please note, however, that future versions of acpivga may remove these sysctl(8) variables without prior notice.

SEE ALSO

     acpi(4), vga(4), sysctl(8)

     Microsoft Corporation, Mobile System Displays and Windows, Version 1.2c, http://www.microsoft.com/whdc/archive/mobiledisplay.mspx, December
     4, 2001.

HISTORY

     The acpivga driver appeared in NetBSD 6.0.

AUTHORS

     Gregoire Sutre <gsutre@NetBSD.org>

CAVEATS

     The acpivga driver only supports PCI/PCI-X/PCI-E display adapters.

     Many ACPI BIOSes implement only part of the ACPI video extensions.  In particular, display output switching via these extensions often does
     not work.	For this reason, acpivga enables hw.acpi.acpivga0.bios_switch by default.  If the display switch hotkey does not work with this
     default setting, try setting hw.acpi.acpivga0.bios_switch to 0.

     Brightness level should be controlled via wsconsctl(8) instead of sysctl(8).

BSD
								 October 28, 2010							       BSD