I have just updated to 12.04 and I have only one choice of screen resolution now, and it is incorrect (1024x768). I believe the correct resolution for my display is 1366 x 768. It is on an Acer Aspire 5338 with Intel GMA 4500M graphics.
In the Diplays window, it is detecting my display as simply 'Laptop'. When I first restarted after the upgrade the screen was scrambled, so I had to restart in recovery mode and select 'Run in failsafe graphic mode', which solved the scrambled screen problem.
Running the command
xrandr: Failed to get size of gamma for output default Screen 0: minimum 1024 x 768, current 1024 x 768 maximum 1024 x 768 default connected 1024x768+0+0 0mm x 0mm 1024x768 0.0*
In System Details, it is reporting the following:
Graphics: VESA Intel(r) Cantiga
Graphics Driver: VESA Intel(r) Cantiga Graphics
Any help would be gratefully received as it is driving me mad trying to resolve it.