Not sure how well I can explain this, but on my Lenovo X61 Tablet (Intel graphics) on Kubuntu 11.04 applications within KDE seem to freeze after a few seconds of use. Moving the mouse cursor to cause some kind of UI element to update seems to cause all frozen applications to continue redrawing a for a few more seconds. For example moving the mouse over a scroll bar or hovering over another window seems to trigger redrawing.
In addition this only happens when compositing is disabled on KWin. I would leave compositing enabled to work around the issue, but I would assume that would increase power consumption of the laptop.
A quick way to reproduce the issue for me is to run ZDoom (software renderer) and the freeze will occur shortly. Another program I noticed the issue with is Xournal (randomly stops drawing until aforementioned triggers at which point all lines drawn appear). I modified ZDoom to print something to the terminal continuously and that solves the issue indicating that the driver might be ignoring screen updates?
Is this a known issue and is there a known work around (outside of using OpenGL compositing of course)?