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Thread: Adjusting screen resolution on a system with no monitor connected.

  1. #1
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    Default Adjusting screen resolution on a system with no monitor connected.

    I'm Using opensuse 13.2 as a server in a very remote location. I use Team Viewer to log in remotely. I've decided to go with Team Viewer because the system is connected via an AT&T 4G hotspot and configuring remote access in the usual way is a pain in the neck due to the cellular network. I have several desktops installed but I prefer to use the standard KDE desktop. With no monitor connected, I am not able to adjust the screen resolution. The current resolution is too low to be of much use. Apart from this screen resolution issue, all of the software functions very well. How can I adjust the screen resolution without a monitor connected? Being able to force a screen resolution would also work. I just need a more friendly screen resolution for remote access. Thanks in advance.

    James.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    You could create a minimal /etc/X11/xorg.conf (or use the newer config files located in /etc/X11/xorg.conf.d) with the desired display mode. The 'gtf' and 'cvt' CLI utilities can be used to generate those.

    For example:

    https://andrewmemory.wordpress.com/2...with-modeline/

    and here's a post describing how to use the dummy Xorg driver with manual configuration

    http://ubuntuforums.org/showthread.php?t=1832456

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    Curious,
    Does Team Viewer allow the display to be re-sized?
    So for instance if TV can be reset to larger resolution, does the openSUSE desktop remain as a smaller resolution?

    The reason why I ask this is that openSUSE has been pretty good about automatically re-sizing displays when viewed over several remote apps(IMO a big feature compared to several other distros). The only time I've seen openSUSE not re-size is when no Desktop is installed (Text only Server install).

    TSU

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    [QUOTE=tsu2;2710043]Curious,
    Does Team Viewer allow the display to be re-sized?

    Yes. As far as I'm aware of it allows whatever resolutions are available on the remote machine. With no monitor connected I'm only getting 1024 x 768.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    Quote Originally Posted by deano_ferrari View Post
    You could create a minimal /etc/X11/xorg.conf (or use the newer config files located in /etc/X11/xorg.conf.d) with the desired display mode. The 'gtf' and 'cvt' CLI utilities can be used to generate those.

    For example:

    https://andrewmemory.wordpress.com/2...with-modeline/

    and here's a post describing how to use the dummy Xorg driver with manual configuration

    http://ubuntuforums.org/showthread.php?t=1832456
    Thanks for the reply. I've tried both creating an xorg.conf file and editing files in xorg.conf.d. No luck so far. It seems like this should be much more straight forward. I don't mind manually editing config files but I thought the software had matured beyond that point. Also, which config files to edit? In years past my edits to the xorg.conf file(s) worked flawlessly. There seems to be some confusion now over how to have absolute control over settings in X11. Someone must have the answer. I really don't feel like wading through tons of X11 docs that might not even apply to my distro anymore.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    It would be useful to know which video chipset is in use here.
    Code:
    /sbin/lspci -nnk | grep '\[03' -A3
    Did you restart the remote X-server after the changes were made?

    Quote Originally Posted by jamesinsandiego View Post
    Thanks for the reply. I've tried both creating an xorg.conf file and editing files in xorg.conf.d. No luck so far.
    Working with a remote machine and no monitor makes this difficult. When working locally, new display modes can be tested using xrandr on the fly. Then they can be added manually using the Xog config files.

    It seems like this should be much more straight forward. I don't mind manually editing config files but I thought the software had matured beyond that point.
    Well, for most Xorg detects the display hardware automatically, so no configuration required. KDE and Gnome have graphical tools that can assist with temporary display mode changes (using xrandr). However, you're in a situation where the resolution is limited because no monitor was present to detect. It is actually possible to buy a black box that fakes an attached display and sends EDID when requested. Some KVM switches can do this as well.

    Also, which config files to edit? In years past my edits to the xorg.conf file(s) worked flawlessly.
    Your choice. The legacy xorg.conf can still be used, or you can use any of the newer config files (as I mentioned previously). AFAIU, it doesn't matter where you put the desired entries as long as the syntax is correct - Xorg is fussy about that.

    There seems to be some confusion now over how to have absolute control over settings in X11. Someone must have the answer. I really don't feel like wading through tons of X11 docs that might not even apply to my distro anymore.
    Start with man xorg.conf - it is current.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    Quote Originally Posted by deano_ferrari View Post
    It would be useful to know which video chipset is in use here.
    Code:
    /sbin/lspci -nnk | grep '\[03' -A3
    Did you restart the remote X-server after the changes were made?


    Working with a remote machine and no monitor makes this difficult. When working locally, new display modes can be tested using xrandr on the fly. Then they can be added manually using the Xog config files.


    Well, for most Xorg detects the display hardware automatically, so no configuration required. KDE and Gnome have graphical tools that can assist with temporary display mode changes (using xrandr). However, you're in a situation where the resolution is limited because no monitor was present to detect. It is actually possible to buy a black box that fakes an attached display and sends EDID when requested. Some KVM switches can do this as well.


    Your choice. The legacy xorg.conf can still be used, or you can use any of the newer config files (as I mentioned previously). AFAIU, it doesn't matter where you put the desired entries as long as the syntax is correct - Xorg is fussy about that.


    Start with man xorg.conf - it is current.

    Thank you very much.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    I've found one way to do this that works for me. I'll document it here. I hope it helps someone else. Open a terminal as root. I use Konsole.

    Use the Xrandr command with no switches:

    VCAdmin@terminal:~> xrandr
    Screen 0: minimum 8 x 8, current 1024 x 768, maximum 32767 x 32767
    VGA1 disconnected (normal left inverted right x axis y axis)
    VIRTUAL1 disconnected (normal left inverted right x axis y axis)

    From this I can see that I want to change “VGA1”

    I issue the command cvt with my desired screen resolution:

    VCAdmin@terminal:~> cvt 1920 1080
    # 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz
    Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync

    I used the Modeline data to add a new mode using the xrandr command:

    xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync

    Then I add the mode to “VGA1” using the xrandr command:

    xrandr --addmode VGA1 1920x1080_60.00

    Finally I adjust the display resolution using ther xrandr command:

    xrandr --output VGA1 --mode 1920x1080_60.00

    Now the xrandr command returns the new mode I configured:

    VCAdmin@terminal:~> xrandr
    Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
    VGA1 disconnected (normal left inverted right x axis y axis)
    1920x1080_60.00 59.96
    VIRTUAL1 disconnected (normal left inverted right x axis y axis)

    This is good. The screen is now my desired resolution. I want to make it permanent so it will occur during system startup. To do this I placed the following lines in /etc/X11/xinit/xinitrc:

    #
    # Add your own lines here...
    #
    xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
    xrandr --addmode VGA1 1920x1080_60.00
    xrandr --output VGA1 --mode 1920x1080_60.00

    I recommend placing those lines right after where it says:

    #
    # Add your own lines here...
    #

    Apparently, that's where they are supposed to go.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    Quote Originally Posted by jamesinsandiego View Post
    I've found one way to do this that works for me. I'll document it here. I hope it helps someone else.
    Yes, using xrandr (as I already hinted at) is a good way to configure/test new display modes, and has been documented in the forums previously, but always good to share again.

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    Default Re: Adjusting screen resolution on a system with no monitor connected.

    Quote Originally Posted by deano_ferrari View Post
    Yes, using xrandr (as I already hinted at) is a good way to configure/test new display modes, and has been documented in the forums previously, but always good to share again.

    Thank You. I guess I just lack the experience to find and use that information which is already in the forum(s). I'm learning more about how to use them now.

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