ACPIVGA(4)

ACPIVGA(4) | Device Drivers 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

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).

October 28, 2010 | NetBSD 9.4