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I am trying to set up this monitor:


I am able to connect the monitor and use it in various screen configurations, but have not yet been able to set it to the correct 1:1 resolution.

The resolution listed for this monitor is 1920 x 1080. This does not appear as an option in the "Displays" GUI when I plug in a VGA cable. So, I attempted to follow the instructions here for adding resolutions:


My attempt:

$ 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

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

$ xrandr --addmode CRT1 1920x1080_60.00X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 156 (RANDR) Minor opcode of failed request: 18 (RRAddOutputMode) Serial number of failed request: 29 Current serial number in output stream: 30

The same thing happened with two different laptops.

In case it helps, this is what the output of xrandr looks like (for one of the laptops):

$ xrandr Screen 0: minimum 320 x 200, current 1366 x 768, maximum 1600 x 1600 LVDS connected 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm 1366x768 60.0*+ 1360x768 60.0
1280x768 60.0
1280x720 60.0
1024x768 60.0
1024x600 60.0
800x600 60.0
800x480 60.0
640x480 60.0
DFP1 disconnected (normal left inverted right x axis y axis) CRT1 connected 1360x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1600x1200 60.0 + 1400x1050 60.0
1600x900 60.0
1280x1024 60.0
1440x900 59.9
1280x960 60.0
1360x768 60.0* 1280x800 59.8
1152x864 60.0
1280x768 59.9
1280x720 60.0
1024x768 60.0
1024x600 60.0
800x600 60.3
800x480 60.0
720x480 60.0
640x480 59.9
1920x1080_60.00 (0xef) 173.0MHz h: width 1920 start 2048 end 2248 total 2576 skew 0 clock 67.2KHz v: height 1080 start 1083 end 1088 total 1120 clock 60.0Hz

The "Displays" GUI gives the following error when I attempt to set up dual-monitor arrangements which would create virtual screens larger than 1600x1600:

"The selected configuration for displays could not be applied: requested position/size for CRTC 148 is outside the allowed limit: position=(1366, 0), size=(1360, 768), maximum=(1600, 1600)"

A maximum of 1600x1600 would rule out the correct resolution, so perhaps this has to do with the problem.

Any suggestions appreciated!

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1 Answer

up vote 1 down vote accepted

I resolved the issue by creating and adding lines to xorg.conf, ignoring whether stuff is working via xrandr.

This is still more or less within the bounds of what the guide at https://wiki.ubuntu.com/X/Config/Resolution suggested;

I just followed the advice in section 6 this time, rather than section 5.

My xorg.conf follows:

Section "Monitor"
    Identifier "External VGA"
    Modeline "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 
    1120 -hsync +vsync
    Option "Rotate" "normal"
    Option "PreferredMode" "1920x1080_60.00"

Section "Screen"
    Identifier "Default Screen"
    Device "Configured Video Device"
    SubSection "Display"
        Virtual 1920 1080

Section "Device"
    Identifier  "Configured Video Device"
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