It took me a while to fix my resolution. I wanted 1280×800@ 60 resolution for my dell laptop. After lot of googling i got some help.
1. sudoedit /etc/X11/xorg.conf. Make following changes:
Section “Monitor”
Identifier “Generic Monitor”
Option “DPMS”
HorizSync 28-64
VertRefresh 43-60
Modeline “1280×800@60” 83.91 1280 1312 1624 1656 800 816 824 841
EndSection
Do determine for modline for your resolution: modline calci. Accordingly you add Modline.
Next in Screen Section keep only resolution that you want.
Section “Screen”
Identifier “Default Screen”
Device “Generic Video Card”
Monitor “Generic Monitor”
DefaultDepth 24
………
………
SubSection “Display”
Depth 24
Modes “1280×800”
EndSubSection
EndSection
After this changes restart X server. Then System >> Preferences >> Screen Resolution and select your resolution.
Hope this will help !!!!
Few useful links
ben robinson’s blog