At the moment X does not really know about widescreen set ups by default. But you can tell it about them.
Hopefully you will have a little program on your machine called 'gtf'. It is used for calculating modelines. It is run from a terminal simple by 'gtf X Y refresh'. So for yours do 'gtf 1920 1200 60'. This would give results like this,
Code:
bash-3.1$ gtf 1920 1200 56
# 1920x1200 @ 56.00 Hz (GTF) hsync: 69.38 kHz; pclk: 178.73 MHz
Modeline "1920x1200_56.00" 178.73 1920 2040 2248 2576 1200 1201 1204 1239 -HSync +Vsync
I do not fully understand what it all means yet (some thing i am working on).
Now you need to put this and some other info into your X config. I have a Samsung 172w, which is a 17inch widescreen running 1240x768@60hz. Below is the part of my xorg.conf that has been changed to make it work. You will have to change parts to suit yours.
Code:
Section "Monitor"
Identifier "My Monitor"
HorizSync 30-81
VertRefresh 60
UseModes "ws"
EndSection
Section "Modes"
Identifier "ws"
Modeline "1280x768" 80.1 1280 1344 1480 1680 768 769 772 795
EndSection
Section "Device"
Identifier "** NVIDIA (generic) [nv]"
Driver "nv"
#VideoRam 131072
# Insert Clocks lines here if appropriate
EndSection
Section "Screen"
Identifier "Screen 1"
Device "** NVIDIA (generic) [nv]"
Monitor "My Monitor"
DefaultDepth 24
Subsection "Display"
Depth 8
Modes "1280x768"
ViewPort 0 0
EndSubsection
Subsection "Display"
Depth 16
Modes "1280x768"
ViewPort 0 0
EndSubsection
Subsection "Display"
Depth 24
Modes "1280x768"
ViewPort 0 0
EndSubsection
EndSection
As you can see I have set it up to only display in widescreen mode. With no other resolutions available. You don not have to do that yourself.