I've just installed Ubuntu 13.04 on my Dell D631 laptop. I was using Windows 7 previously which coped perfectly with my set up. I dock it all the time in a docking station so that I can use two Dell FP1708FP monitors and keep the laptop lid shut. I believe the laptop has a Radeon X1200 series onboard graphics card (reported as Gallium 0.4 on ATI RS690 in ubuntu settings).
In Windows 7 it was quite happy to un-mirror the displays and allow an extended desktop at resolution of 1280x1024 on both screens. But Ubuntu cannot seem to cope with setting the resolution to anything other than 1024x768 or 1152 x 864. If I try to set both monitors to the native resolution of 1280x1024 I get an error that it's beyond the capability of the 3D device. I've tried a number of things including running xrandr which reports that both VGA-0 and DVI-0 are capable of 1280x1024 and installing ARandR.
ARandR provided better results in that I could set the resolution how I wanted but then the displays seem to corrupt as if it was bad video memory, with half a window on both screens and two mouse pointers showing at certain points of the screen (one on one screen and one on the other as if mirroring were happening, but not all over the screen)
Anyone know how I can set both external monitors (one attached via VGA cable and the other attached via DVI) can be set to 1280x1024?