How to add display resolution for an LCD in Ubuntu 12.04? xrandr problem

Question

I am new to Ubuntu. I have installed Ubuntu 12.04 and am stuck trying to set up the correct resolution for my LCD display.

The native resolution for the LCD is 1920x1080

here is the output from xrandr:

$ xrandr
Screen 0: minimum 320 x 200, current 1280 x 720, maximum 4096 x 4096
LVDS1 connected 1280x720+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1280x720 60.0*+
800x600 60.3 56.2 
640x480 59.9
VGA1 disconnected (normal left inverted right x axis y axis)

Then I create new modeline:

$ cvt 1920 1080 60
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

So far so good. Then I create new mode using xrandr:

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

But for some reason that new mode was created for VGA (VGA1) output instead of LCD output (LVDS1):

$ xrandr
Screen 0: minimum 320 x 200, current 1280 x 720, maximum 4096 x 4096
LVDS1 connected 1280x720+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1280x720 60.0*+
800x600 60.3 56.2 
640x480 59.9 
VGA1 disconnected (normal left inverted right x axis y axis)
1920x1080_60.00 (0xbc) 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

So, if I try to add mode to LVDS1, I get an error:

$ xrandr --addmode LVDS1 "1920x1080_60.00"
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 149 (RANDR)
Minor opcode of failed request: 18 (RRAddOutputMode)
Serial number of failed request: 25
Current serial number in output stream: 26

Adding that new mode to VGA1 works fine, but I don't use that VGA1 output.

Answer 1

You can add missing resolutions to Ubuntu 12.04 using xrandr.

First, use cvt to create a new resolution mode.

sudo cvt 1920 1080 60

Part of the output should be similar to this: "Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync" (w/o the quotes).

Next, declare a new resolution mode.

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

Next, find out the name of your video device.

sudo xrandr -q

Mine was named "Virtual1" (running a virtual machine). Once you know the name of your device, you can, finally, add your new resolution mode to the device/system.

sudo xrandr --addmode Virtual1 1920x1080_60.00

See more information in the "Adding undetected resolutions" section here: https://wiki.ubuntu.com/X/Config/Resolution/#Adding_undetected_resolutions

Answer 2

This link helped me.

In short: run xrandr and cvt like you did, then create the following file:

/usr/share/X11/xorg.conf.d/10-monitor.conf

In the file change the parameters in < > according to your specs:

Section "Monitor"
  Identifier "Monitor0"
  <INSERT MODELINE HERE>
EndSection
Section "Screen"
  Identifier "Screen0"
  Device "<INSERT DEVICE HERE>"
  Monitor "Monitor0"
  DefaultDepth 24
  SubSection "Display"
    Depth 24
    Modes "<INSERT MODENAME HERE>"
  EndSubSection
EndSection