1.\" $NetBSD: acpivga.4,v 1.3 2010/10/28 21:45:02 gsutre Exp $ 2.\" 3.\" Copyright (c) 2010 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 16.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 17.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 19.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25.\" POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd October 28, 2010 28.Dt ACPIVGA 4 29.Os 30.Sh NAME 31.Nm acpivga 32.Nd ACPI Display Adapter and Output Devices 33.Sh SYNOPSIS 34.Cd "acpivga* at acpi?" 35.Cd "acpiout* at acpivga?" 36.Sh DESCRIPTION 37The 38.Nm 39driver provides generic support for brightness control and output switching, 40through 41.Tn ACPI 42video extensions. 43The 44.Tn ACPI 45specification requires that systems containing a built-in display adapter 46implement these extensions in their 47.Tn ACPI 48BIOS. 49.Pp 50The driver handles brightness hotkeys and display switch hotkeys. 51In addition, the following 52.Xr sysctl 8 53read/write variables are provided (when hardware support is available): 54.Bl -tag -width Ds 55.It Va hw.acpi.acpivga0.bios_switch 56BIOS output switching policy. 57This boolean variable controls the behavior of the BIOS when a display 58switch hotkey is pressed. 59.Bl -tag -width xxx -compact 60.It Sy 1 61the BIOS should automatically switch outputs, with no interaction from 62.Nm . 63.It Sy 0 64the BIOS should only notify 65.Nm 66of the desired output state changes. 67.El 68.It Va hw.acpi.acpiout0.brightness 69Brightness level. 70This integer variable typically ranges from 0 to 100, but any integer value 71is accepted (the driver uses the closest brightness level supported by the 72device). 73.El 74.Pp 75Please note, however, that future versions of 76.Nm 77may remove these 78.Xr sysctl 8 79variables without prior notice. 80.Sh SEE ALSO 81.Xr acpi 4 , 82.Xr vga 4 , 83.Xr sysctl 8 84.Rs 85.%A Microsoft Corporation 86.%D December 4, 2001 87.%T Mobile System Displays and Windows 88.%N Version 1.2c 89.%U http://www.microsoft.com/whdc/archive/mobiledisplay.mspx 90.Re 91.Sh HISTORY 92The 93.Nm 94driver appeared in 95.Nx 6.0 . 96.Sh AUTHORS 97.An Gr\('egoire Sutre 98.Aq gsutre@NetBSD.org 99.Sh CAVEATS 100The 101.Nm 102driver only supports PCI/PCI-X/PCI-E display adapters. 103.Pp 104Many 105.Tn ACPI 106BIOSes implement only part of the 107.Tn ACPI 108video extensions. 109In particular, display output switching via these extensions often does not 110work. 111For this reason, 112.Nm 113enables 114.Va hw.acpi.acpivga0.bios_switch 115by default. 116If the display switch hotkey does not work with this default setting, try 117setting 118.Va hw.acpi.acpivga0.bios_switch 119to 0. 120.Pp 121Brightness level should be controlled via 122.Xr wsconsctl 8 123instead of 124.Xr sysctl 8 . 125