acpivga(4) - NetBSD Manual Pages

ACPIVGA(4)              NetBSD 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 inter-
                  action 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).

NetBSD 9.3                     October 28, 2010                     NetBSD 9.3