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
Grégoire 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).