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HOWTO_nVidia_TwinView

Contents

Introduction

This guide will explain, in step-by-step fashion, how to use nVidia's TwinView dual monitor setup. While other guides will give whole examples, none of them explain which options do exactly what, which are optional, and which have further settings. This will be covered here.

Requirements

A recent and up-to-date version of the nvidia-drivers or nvidia-legacy-drivers package is required for TwinView operation. This guide will not function on the XOrg or XFree 'nv' driver. The graphics card will need to have more than one head. Twinview does not span multiple cards.

USE Flags

The "xinerama" USE flag can be used to compile most common window managers with multiple monitor support. This greatly improves the way it places windows and lets it use features specific to seeing more than one screen's edges. Without it, TwinView will still function normally, however the desktop experience will be affected.

XOrg Configuration

All of the following options will appear under the Device section of xorg.conf:

Option    "TwinView"

Required option. Enables TwinView.


Option    "MetaModes" "DFP-0: 1600x1200, CRT-0: 1600x1200; DFP-0: 1600x1200, CRT-0: NULL; DFP-0: NULL, CRT-0: 1600x1200"
--OR--
Option    "MetaModes" "1600x1200,1600x1200; 1600x1200,NULL; NULL,1600x1200"

Required option. Specified in two parts, the resolution of the first monitor followed by the resolution of the second. Each pair of resolutions must be used together to form an entire screen spanning two monitors. Each MetaMode section is separated by a semi-colon. NULL can be used to specify a monitor that will either not be used or is disconnected. This is useful if both monitors will not always be connected and will allow X to start even though both display devices are not present. Device names can be used for clarity.


Option    "ConnectedMonitor" "DFP-0,DFP-1"

Optional. Used to specify which monitors are connected to the video card. Two LCD panels are listed in the example above. This can be any combination of CRT or DFP devices. If this option is not entered, the first device will always be a CRT if your card has an analog output. This command is deprecated in driver version 8756 for the UseDisplayDevice option.

Warning: nVidia recommends that this option not be used except in extreme circumstances, such as connecting a KVM or using a monitor that does not support DDC.


Option    "UseDisplayDevice" "DFP-0,DFP-1"

Optional. Identical to ConnectedMonitor, but is used in driver versions 8756 and above.

Warning: nVidia recommends that this option not be used except in extreme circumstances, such as connecting a KVM or using a monitor that does not support DDC.


Option    "HorizSync" "DFP-0: 30-81; CRT-0: 30-98"

Required option. Specifies horizontal refresh rates for each monitor. Rates can be a single value instead of ranges.


Option    "VertRefresh" "DFP-0: 56-75; CRT-0: 50-160"

Required option. Specifies vertical refresh rates for each monitor. Rates can be a single value instead of ranges.


Option    "TwinViewOrientation" "CRT-0 RightOf DFP-0"

Optional. Specifies which order monitors are displayed in relation to the current desktop. In this example, DFP-0 is a monitor which is sitting to the right side of CRT-0. If this option is not entered, the first device will be shown to the right of the second device. Available options are RightOf, LeftOf, Above, Below, and Clone.


Option    "NoTwinViewXineramaInfo" "true"

Optional. Normally, TwinView will send Xinerama information to X so that window managers and desktop environments can see the dual monitor setup. (except when you are using nvidia-settings see here for a workaround) This will turn off this information, and programs will act as if the two monitors are one large screen.


Option "TwinViewXineramaInfoOrder" "DFP-0"

This will change your primary monitor to any monitor you select, for example to show gdm on a specific monitor. (Only available in 1.0.9xxx and above)

Non-TwinView Specific Options

Option    "RenderAccel" "true"

Optional. This is not a TwinView specific option, but is a very good idea to achieve optimal rendering performance. Rendering two displays will be much slower without it.


Option    "UseEdidDpi" "false"

Optional. Used in case a monitor either fails to or incorrectly reports its DPI settings. An incorrect setting will cause fonts to appear larger or smaller than they should be. Setting this option will use X default DPI settings.


Option    "DPI" "72x72"

Optional. Used in tandem with UseEdidDpi to specify a DPI setting other than the one reported by X.

Working Example

The following is a working example for an nVidia graphics card featuring one analog output and one DVI output. The analog output is connected to a high quality CRT and the DVI is connected to an LCD.

Section "Device"
    Identifier    "Card0"
    VendorName    "eVGA"
    BoardName     "Geforce 6600GT"
    Driver        "nvidia"
    Option        "TwinView"
    Option        "UseDisplayDevice" "CRT-0,DFP-0"
    Option        "HorizSync" "CRT-0: 30-98; DFP-0: 30-81"
    Option        "VertRefresh" "CRT-0: 50-160; DFP-0: 56-75"
    Option        "MetaModes" "1600x1200,1600x1200; 1600x1200,NULL; NULL,1600x1200"
EndSection

Links

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Last modified: Thu, 09 Oct 2008 07:46:00 +0000 Hits: 14,271