ACPIVGA(4) FreeBSD 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 specification
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
closest 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 <
[email protected]>
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).
FreeBSD 14.1-RELEASE-p8 October 28, 2010 FreeBSD 14.1-RELEASE-p8