running x-server without a monitor - X

This is a discussion on running x-server without a monitor - X ; Hi i want to do some renderering with an opengl graphic card on an linux server. But the graphic card is not physically connected to a monitor. therefore the starting of the the x server always fails with the error ...

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  1. running x-server without a monitor

    Hi
    i want to do some renderering with an opengl graphic card on an linux server. But the graphic card is not physically connected to a monitor.
    therefore the starting of the the x server always fails with the error "no screens found". if i physically connect the monitor it is working.
    is there a special configuration issue that i have to consider.

    Thanks for any help

    Johannes

  2. Re: running x-server without a monitor

    On Sat, 8 Jan 2005 21:20:24 +0100, Johannes Bühler staggered into the
    Black Sun and said:

    Please fix Sylpheed's line wrapping so that it wraps at 72 characters.

    > i want to do some renderering with an opengl graphic card on an linux
    > server. But the graphic card is not physically connected to a monitor.


    ? What? In most cases under Linux, accelerated OpenGL rendering only
    works from the graphics card to a directly-connected monitor. The GLX
    and MIT-SHM and other useful extensions that you need for accelerated
    OpenGL rendering are not available if you're transferring the X data
    over the network IIRC. Maybe you'd better explain exactly what it is
    you want to do. (Use German to do that if you don't feel comfortable
    with English; a number of German-speakers read this newsfroup.)

    > therefore the starting of the the x server always fails with the error
    > "no screens found".


    Well, yeah. If there's no monitor connected, there's a Screen section
    in the config file, and that Screen is mentioned in ServerLayout, X will
    not start unless the monitor present in that Screen section is connected
    directly to the graphics card. There may be a way to use a "null"
    monitor for this; I don't know if that will help you though. OpenGL
    rendering is not accelerated unless the final screen is a
    locally-connected monitor.

    > if i physically connect the monitor it is working. is there a special
    > configuration issue that i have to consider?


    Just the things I mentioned above. HTH anyway,

    --
    Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
    Brainbench MVP for Linux Admin / mail: TRAP + SPAN don't belong
    http://www.brainbench.com / Hire me!
    -----------------------------/ http://crow202.dyndns.org/~mhgraham/resume

  3. Re: running x-server without a monitor


    > Please fix Sylpheed's line wrapping so that it wraps at 72 characters.
    >

    it is. so whats wrong?

    > > i want to do some renderering with an opengl graphic card on an linux
    > > server. But the graphic card is not physically connected to a monitor.

    >
    > ? What? In most cases under Linux, accelerated OpenGL rendering only
    > works from the graphics card to a directly-connected monitor. The GLX
    > and MIT-SHM and other useful extensions that you need for accelerated
    > OpenGL rendering are not available if you're transferring the X data
    > over the network IIRC. Maybe you'd better explain exactly what it is
    > you want to do.

    some geographically software i am using needs an opengl complient graphics card to do the rendering. Therefore also an running Xserver is needed. right? i just wanted to know if there is an way to have a linux box with an opengl graphics card and profit from hardware accelerated rendering but without having a monitor connected to the card.

    Doing some more googling i have found Xvfb. Does it work together with the opengl graphics card?

    Johannes


    > Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
    > Brainbench MVP for Linux Admin / mail: TRAP + SPAN don't belong
    > http://www.brainbench.com / Hire me!
    > -----------------------------/ http://crow202.dyndns.org/~mhgraham/resume


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