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dninja

Member

From: Sheffield, UK

Registered: 2006-04-29

Posts: 374

Website

trying to understand dual displays

I've recently got a second monitor and got it setup and running with fluxbox but after reading loads of posts about two monitors I have a few questions:

Currently each monitor runs its own screen, if I start firefox in one then try to access it from the other I get a message saying that it knows that it is already running but it can't connect to it. I assume this is because of having multiple screens. How can I get around this? I'd like to be able to click a link in evolution in one screen and have the page open in firefox regardless of which screen it is on (i.e. I don't want to add --display ... on the command line).

I can't drag windows between screens. Again, i assume this is because of multiple screens. I've been told xinerama would help this but I've seen quite a few posts with people shouting about how bad xinerama is. Can people comment, and if it is as bad as some people say, is there an alternative?

Lastly, both monitors are lcd but the one plugged into the dvi socket has a pink tinge to it, the one on svga has a blue tinge. Someone said this is normal due to the digital output from dvi, is it?

Ta

JGC

Developer

Registered: 2003-12-03

Posts: 1,664

Re: trying to understand dual displays

Xinerama is just an extension to the X11 protocol that is used to define dualscreen outlines. Xinerama is really useful, without it, your maximized windows will stretch over two screens and popups will appear in the middle of your 2560x1024 desktop.

To get real dualscreen, there's quite some options available:
- Nvidia using twinview
- ATI's fglrx using special monitor layouts
- Xinerama by just putting two display devices together
- MergedFB, where you have one big fat screen and Xinerama gets emulated

When using nvidia or ati, use the drivers method. When using opensource drivers, if you have a dualhead card and your driver supports it (sis, ati, mga and possibly intel), use MergedFB, it has many advantages over the regular Xinerama extension, one of them is speed, the other is maintaining DRI on matrox cards.

When using different videocards to get your dualhead configuration, xinerama is the only way to go.

dninja

Member

From: Sheffield, UK

Registered: 2006-04-29

Posts: 374

Website

Re: trying to understand dual displays

Xinerama is just an extension to the X11 protocol that is used to define dualscreen outlines. Xinerama is really useful, without it, your maximized windows will stretch over two screens and popups will appear in the middle of your 2560x1024 desktop.

Mine don't, they don't seem to even want to acknowledge each others presence.

To get real dualscreen, there's quite some options available:
- Nvidia using twinview
- ATI's fglrx using special monitor layouts
- Xinerama by just putting two display devices together
- MergedFB, where you have one big fat screen and Xinerama gets emulated

should have said, I am using nvidia on a dual head with twinview at the moment. From the sound of it dual screen is having the two independant screens, if so then I don't want it! I want to be able to drag windows from one screen to the other and to be able to run commands in one and have it access windows in the other.

Am I right in thinking MergeFB is ATI only?

Borosai

Member

From: Sandy Appendix, U.S.A.

Registered: 2006-06-15

Posts: 227

Re: trying to understand dual displays

Well, if you are using nvidia/twinview already, setting it up shouldn't be too complicated. I have a similar setup, except both of my monitors are connected via DVI. I am posting my xorg.conf below to give you an idea of what may be needed, although some things won't apply to your case (naming schemes, modules, etc). At the moment, the setup works just fine, but I have been meaning to clean it up and make sure nothing is wrong (which I'm not at the moment...but it works ). The DEVICE section is what you want to look at for now. If you have any questions about something in the file, let me know.

Section "ServerLayout"
    Identifier    "nVidiaTwinView_2560x1024"
    Screen        0                "DualHead_2560x1024"
    InputDevice    "LogitechUltra-X"        "CoreKeyboard"
    InputDevice    "WirelessIME2.0"        "CorePointer"
EndSection


Section "ServerFlags"
    Option        "AllowMouseOpenFail"        "false"
    Option        "BlankTime"            "0"
    Option        "StandbyTime"            "10"
    Option        "SuspendTime"            "0"
    Option        "OffTime"            "0"
    Option        "Xinerama"            "false"    
EndSection


Section "Files"
    RgbPath    "/usr/share/X11/rgb"
    ModulePath    "/usr/lib/xorg/modules"
    FontPath    "/usr/share/fonts/100dpi"
    FontPath    "/usr/share/fonts/75dpi"
    FontPath    "/usr/share/fonts/TTF"
    FontPath    "/usr/share/fonts/Type1"
    FontPath    "/usr/share/fonts/artwiz-fonts"
    FontPath    "/usr/share/fonts/cyrillic"
#    FontPath    "/usr/share/fonts/encodings"
    FontPath    "/usr/share/fonts/local"
    FontPath    "/usr/share/fonts/misc"
#    FontPath    "/usr/share/fonts/util"
EndSection


Section "Module"
    Load        "dbe"
    Load        "ddc"
    Load        "extmod"
    Load        "type1"
    Load        "freetype"
    Load        "bitmap"
    Load        "glx"
#    Load        "dri"
    Load        "record"
    Load        "xtrap"
EndSection


Section "InputDevice"
    Identifier    "LogitechUltra-X"
    Driver        "keyboard"
    Option        "CoreKeyboard"
    Option        "XkbRules"            "xorg"
    Option        "XkbModel"            "pc104"
    Option        "XkbLayout"            "us"
#    Option        "XkbVariant"            ""
#    Option        "XkbOptions"            ""
EndSection


Section "InputDevice"
    Identifier    "WirelessIME2.0"
    Driver        "mouse"
    Option        "CorePointer"
    Option        "Protocol"            "ExplorerPS/2"
    Option        "Device"            "/dev/psaux"
    Option        "Buttons"            "5"
    Option        "ButtonMapping"        "1 2 3 6 7"
    Option        "ZAxisMapping"        "4 5"
    Option        "Emulate3Buttons"        "false"    
EndSection


Section "Device"
    Identifier    "nVidiaQuadroFX1300"
    VendorName    "PNY Technologies"
    BoardName    "NV38GL [nVidia Quadro FX 1300]"
    Driver        "nvidia"
    BusID        "PCI:4:0:0"
    Option        "NoLogo"            "true"
    Option        "RenderAccel"            "true"
    Option        "TwinView"            "true"
    Option        "TwinViewOrientation"        "RightOf"
    Option        "MetaModes"            "1280x1024,1280x1024; 1280x1024,NULL"
    Option        "ConnectedMonitor"        "DFP-0,DFP-1"
    Option        "SecondMonitorHorizSync"    "28.00 - 64.00"
    Option        "SecondMonitorVertRefresh"    "60.00"
    Option        "UseEdidDpi"            "false"
    Option        "DPI"                "96x96"
EndSection


Section "Monitor"
    Identifier    "DFP-0"
    VendorName    "Sony Corporation"
    ModelName    "SDM-S74"
    HorizSync    28.00 - 64.00
    VertRefresh    60.00
    Option        "DPMS"
EndSection


Section "Monitor"
    Identifier    "DFP-1"
    VendorName    "Sony Corporation"
    ModelName    "SDM-S74"
    HorizSync    28.00 - 64.00
    VertRefresh    60.00
    Option        "DPMS"
EndSection


Section "Screen"
    Identifier    "DualHead_2560x1024"
    Device        "nVidiaQuadroFX1300"
    Monitor        "DFP-0"
    DefaultDepth    24
    SubSection    "Display"
        Depth        24
        Modes        "1280x1024"
        ViewPort    0 0
    EndSubSection
EndSection

dninja

Member

From: Sheffield, UK

Registered: 2006-04-29

Posts: 374

Website

Re: trying to understand dual displays

Thanks for that, I'll give it a try later when I get chance to restart X.

dninja

Member

From: Sheffield, UK

Registered: 2006-04-29

Posts: 374

Website

Re: trying to understand dual displays

I now have two screen which work together. I removed the Twinview line and added

Section "ServerFlags"  
    Option "Xinerama" "true" 
EndSection

to the file.

I've now got two co-operating screens.

I had an initial panic of the fluxbox toolbar being split over the middle of the two screens but playing with the positioning and settings it is now happily at the bottom of one of them.