http://bugs.winehq.org/show_bug.cgi?id=27156
--- Comment #62 from Dan Kegel dank@kegel.com 2011-06-05 10:17:18 CDT --- Looks like this is the post you found: http://lists.x.org/archives/xorg-devel/2010-September/012757.html
His message had two suggestions in it. The second one "if you're not using the cursor itself because you're e.g. rendering your own or it's not needed by the application, you can grab the slave devices directly and detach them. in that case you don't have to worry about warp pointer at all." also sounds interesting...