Keystroke buffer outruns window scrolling

Window scrolling speed is limited on some hardware and X configurations. The keystroke buffer stores a number of strokes, so that if a user holds the 'up' and 'down' arrow keys the window keeps scrolling after the key is released. The window is locked and might even grey out until scrolling catches up with the keystroke buffer. Ubuntu looks crusty and feels unresponsive with this behaviour.

A suggested improvement is to make window scrolling sensitive to change in keystroke number rather than explicit number of keystrokes, or to detect when the arrow keys are being held down.

This behaviour has been noted with Ubuntu Intrepid on a Sony Vaio PCG-V505DX notebook, lspci and Xorg.0.log attached.