http://bugs.winehq.org/show_bug.cgi?id=6971
--- Comment #184 from Forest Hale lordhavoc@ghdigital.com 2008-10-17 17:40:40 --- That is incorrect.
DGA shared memory video was deprecated because it required superuser privileges (essentially it mapped the video memory into application memory space, so that a game could draw stuff at the fastest possible speed, provided that the window was completely uncovered).
In essence, it was useless for security reasons.
DGA mouse grab has never been deprecated, and is still fully supported in most xorg input modules (evdev did not support it until recently though).
I don't see any reason that DGA mouse grab would ever be deprecated without a better replacement, and as long as it does work we should use it (it is a queryable extension after all).