> Is this with or without using X to draw the cursor? If it's Allegro
> drawing the cursor, it's probably Xlib hitting an async as it tries to
> draw the mouse in the timer thread and something else elsewhere.
This happens with X handling the mouse cursor. It also happens in 4.1.15 with
Allegro drawing the mouse cursor.
I'm not sure how to fix this either (as I'm not even sure why this becomes a
problem on a multi-processor machine and not a single-processor one). I think
it's not that important to fix in a hurry as most people won't use a
multi-processor machine - unless the problem can be reproduced on a plain
Pentium with hyper threading.