Hi there folks,

I have recently been given an old LCD. It works great with Ubuntu at full resolution 1280x1024 60hz but I'm currently working on a game that runs at 320x200. I'm using SDL for this and the resolution changes just fine, the problem is that the refresh rate appears to get set at 70Hz and the LCD shows an "Out of range" warning that doesn't go away.

I think I'm looking for a setting in the Xorg.conf file to force the refresh rate to 60hz but the config file in ubuntu is pretty sparse: here it is:



# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "gb"
EndSection

Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
EndSection

Section "Device"
Identifier "Configured Video Device"
Driver "nvidia"
Option "ReferenceClock" "29.500MHz"
EndSection

Section "Monitor"
Identifier "Configured Monitor"
HorizSync 30 - 72
VertRefresh 50 - 85
EndSection

Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
Defaultdepth 24
Option "AddARGBGLXVisuals" "True"
EndSection

Section "ServerLayout"
Identifier "Default Layout"
screen "Default Screen"
EndSection

Section "Module"
Load "glx"
Load "vnc"
EndSection

The first thing to do directly related to your problem, is to adjust the "VertRefresh" line in the "Monitor" section.
Change it to read:

VertRefresh 60.0

or if it complains about not having a low-high range (it might, but probably not) then use:

VertRefresh 60.0 - 60.0

Ideally though, even though it is an LCD panel, it probably has a small range at which it is designed to operate. Check online for the user guide or owner manual for the monitor, or in the actual user guide if you have it, or on the label on back of the monitor, and get the manufacturers intended specs for the horiz and vert refresh, and set them accordingly.

You will need to reboot or kill/restart X with CTRL-ALT-BACKSPACE for the changes to be in effect.

Fantastic, that fixed it!

Can't believe I didn't see that really...

Thanks a lot dude!