I have a midrange PC (Intel Core2-Duo 3GHz, 4GB RAM, 1.5TB storage), with latest Ubuntu 11.10 (Oneiric) and Unity (3D).
Description: PC does NOT always return control after automatic timeout to screen-saver -- does NOT prompt for password, keyboard and mouse are still active but NON-functional, and is non-recoverable (requires power-off).
This appears to be a race condition between mouse and keyboard. When I absently move mouse (to exit screensaver) and then quickly enter password (unprompted), this lockup condition occurs ..
Is this a known issue? Can it be resolved?
A similar mouse/keyboard zombie-state is described in: (but for Ubuntu 11.04)
Freeze when resuming from screensaver or monitor-sleep-state
UPDATE
Since update to kernel 3.0.0-14 (today) this has happened 3 times.