NAME
acpivga —
ACPI Display Adapter and Output
Devices
SYNOPSIS
acpivga* at acpi?
acpiout* at acpivga?
DESCRIPTION
Theacpivga 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
acpivgaof 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
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).