====== xrandr ======
===== creaete new mode =====
copied from: http://ubuntuforums.org/showthread.php?t=1112186
worked on ubuntu natty (11.10)


Here are the steps

Use xrandr to make sure that the new mode can fit within the maximum framebuffer size
    xrandr | grep maximum

Use gtf to create a mode line (gtf <pixel horizontal> <pixel vertical> <frequency>)
    gtf 1440 900 59.9

Add new mode using xrandr (xrandr --newmode <name of new mode> <output of gtf-command>
    xrandr --newmode "1440x900_59.90"  106.29  1440 1520 1672 1904  900 901 904 932  -HSync +Vsync

Add this newly added mode to the desired output (VGA/LVDS etc)
    xrandr --addmode VGA 1440x900_59.90

Choose the new mode
    xrandr --output VGA --mode 1440x900_59.90



==== TO MAKE THE CHANGES PERSISTENT ====

    sudo gedit /etc/X11/xorg.conf

Find this: (yours might look different than from below)
Section "Screen"
Identifier "Primary Screen"
Device "ATI Technologies, Inc. M22 [Radeon Mobility M300]"
EndSection

and add this to it

DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1280x1024" "1024x768" "640x480"
EndSubSection

so it should all look similar to this:

Section "Screen"
Identifier "Primary Screen"
Device "ATI Technologies, Inc. M22 [Radeon Mobility M300]"
DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1280x1024" "1024x768" "640x480"
EndSubSection
EndSection


MAKE SURE YOU ADD YOUR NEW RESOLUTION TO THE MODES LINE
Modes "1280x1024" "1024x768" "640x480"

==== increase framebuffer ====

In case the frame buffer size is a limitation for the resolution you want to add (it happened to me), just modify/create the "Virtual" parameter in the "Display" subsection of your xorg.conf. Here's how mine looks after configuring the frame buffer size to use my 22' widescreen (resol: 1680x1050)...

<code>

Section "Screen"
	Identifier	"Default Screen"
	Monitor		"Configured Monitor"
	Device		"Configured Video Device"
	SubSection "Display"
		Virtual	2960 1050
		Depth 24
		Modes "1680x1050" "1280x800"
	EndSubSection
EndSection

</code>