Dual monitor not work in ubuntu 12.04.4 LTS

[sivakumar2]

Hi ,
I have ubuntu 12.0.4 LTS and connected with dual monitors . It was working fine without any issues. Allof sudden one my monitor did not give any display . I tried all the troubleshooting by changing cable both vga and DVI but no luck. I am sure my DVI cable is good. Even after the DVI cable changed , no output.

#lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04.4 LTS
Release: 12.04
Codename: precise

xrand output
#xrandr | more
Screen 0: minimum 320 x 200, current 1920 x 1200, maximum 32767 x 32767
LVDS1 connected (normal left inverted right x axis y axis)
1440x900 60.0 + 59.9 50.0
1360x768 59.8 60.0
1152x864 60.0
1024x768 60.0
800x600 60.3 56.2
640x480 59.9
VGA1 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 60.0*+
1920x1080 59.9
1600x1200 60.0
1680x1050 60.0
1280x1024 75.0 72.0 60.0
1440x900 75.0 59.9
1024x768 75.1 70.1 60.0
800x600 72.2 75.0 60.3
640x480 72.8 75.0 66.0 60.0
720x400 70.1
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
1280x1024_60.00 (0xc0) 109.0MHz
h: width 1280 start 1368 end 1496 total 1712 skew 0 clock 63.7KHz
v: height 1024 start 1027 end 1034 total 1063 clock 59.9Hz

[toms3d]

Not sure what you did to test. but if you switch cables with outputs,monitor should work or not. Or are interfaces not the same. Do not know what kind of monitor. crt or lcd. lcd usually fail back light because electrolytic caps fail and backlight goes out.
Different sizes or resolutions may cause problem.

It seems that both are 1920x1200, But I donot claim that is defined by the output shown.

so you can also reverse right and left by this in an xterm.
xrandr --output LVDS1 --auto --right-of VGA1
or switch LVDS1 and VGA1 or use --left-of