How to change the color depth?

Question

I have Ubuntu 10.04 installed on a Dell C600 and the highest available resolution is 800x600. From my previous I remember 1024x768 would work after setting the colour depth to 16bit, but there is no xorg.conf in /etc/X11 anymore. So, how can the colour depth be changed on lucid lynx?

Answer 1

You can create a new xorg.conf by switching into a virtual virtual console (Ctrl + Alt + (F1-F6)) and running sudo service gdm stop.

Then run Xorg -configure (yes, it should be Xorg, not xorg). If you had an old xorg.conf file in /etc/X11/ you'd first back that up by doing sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.backup.

Then move your newly created xorg.conf to /etc/X11/ by running sudo mv xorg.conf.new /etc/X11/xorg.conf and restart gdm by running sudo service gdm start.

Then you can change the color depth in there by finding the appropriate section and changing/adding whatever's in there to DefaultDepth 16

Answer 2

The following is verified on Ubuntu 13.04:

Try doing this step: http://ubuntuforums.org/showthread.php?p=9362728#post9362728 , but before you get to the sudo service gdm start part, change (or add if there were none) the screen section (within the xorg.conf file) to something like:

Section "Screen"
Identifier    "Default Screen"
Monitor        "Configured Monitor"
Device        "Configured Video Device"
DefaultDepth    24
EndSection

In my case, depth used to be 32; I changed it to 24 to free some display memory so that I can plug a huge LCD display to it.

Answer 3

Try doing this step, but before you get to the sudo service xdm start part, change the screen section (within the xorg.conf file) to something like:

Section "Screen"
Identifier    "Default Screen"
Monitor        "Configured Monitor"
Device        "Configured Video Device"
DefaultDepth    16
Modes        "1024x768"
EndSection