Comment 6 for bug 945749

Same problem here. This is on a Fujitsu-Siemens Amilo Pa1510, running 12.04/i386. Installation from a network upgrade. The graphics chipset ist described as:

01:05.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RS482 [Radeon Xpress 200M]

The mouse (trackpad) is only jerky/freezing on the login screen. Once logged it, it (seem to) work just fine. It's annoying because this graphic chipset works best in Unity2D, I get strange artifacts with the default settings (at least I used to on 11.10 it was resolved by using Unity2D). Now it's next to impossible to switch to 2D.