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frepie
Asked: 2016-01-04 18:32:11 +0800 CST

Screen resolution 1440x900 not listed

  • 772

I just got a new nvidia graphics card that works fine at 1440x900 under window (dual boot setup). Unfortunately, my monitor is not recognized by ubuntu. Here is my xrandr -q output

Screen 0: minimum 8 x 8, current 1360 x 768, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DVI-D-0 connected primary 1360x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1024x768       60.0 +
1360x768       60.0*    59.8  
1152x864       60.0  
800x600        72.2     60.3     56.2  
680x384        60.0     59.8  
640x480        59.9  
512x384        60.0  
400x300        72.2  
320x240        60.1  
1440x900_60.00 (0x1e7)  106.5MHz
   h: width  1440 start 1528 end 1672 total 1904 skew    0 clock   55.9KHz
    v: height  900 start  903 end  909 total  934           clock   59.9Hz

I manage to add the desired resolution (1440x900) but when I do 

xrandr --output DVI-D-0 --mode 1440x900_60.00

I get 

xrandr: cannot find mode 1440x900_60.00
nvidia

2 Answers

  1. Best Answer

    Ok Mystery is over: I changed my DVI cable to a vga cable with a vga to DVI adapter and suddenly, Ubuntu is able to recognize my monitor and set the correct resolution. Maybe this is that way because my monitor is pretty old. This is in no way a correct answer to the larger problem i.e. the inability to set the correct resolution through xrandr but I will live with it.

    • 3

  2. You need to create a new mode and apply it.

    The commands to be executed in order:

    cvt 1440 900
xrandr --newmode "1440x900_60" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync

    The part of the line after xrandr --newmode is similar to the ouput you should get when using the cvt command, so copy the output from the "resolution_refreshRate" ("1440x900_60" here) point to the +vsync point and add it to xrandr --newmode.

    Then:

    xrandr --addmode LVDS1 resolution_refreshRate (don't use speechmarks)
xrandr --output LVDS1 --mode resolution_refreshRate

    If you want to make the changes permanent:

    • Create a bash script, xrandr.sh for example, and place your xrandr commands into it: 

      #!/bin/bash
sudo xrandr --newmode ""1440x900_60"" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
sudo xrandr --addmode LVDS1 1440x900_60
xrandr --output LVDS1 --mode 1440x900_60

    • Make the script executable with chmod +x xrandr.sh

    • Search for "Startup Applications" in the dash, run it, and add the script as a startup application.

    The commands will now run every time you log into your account.

    Note: I'm using LVDS1 as the supposed monitor name, but yours probably won't be the same. You can find your monitor name using:

    xrandr | grep " connected " | awk '{ print$1 }'

    All the above can be done for you with this program - including the startup script.

    • 1