I'm assuming that this patch http://cgit.freedesktop.org/mesa/mesa/commit/?id=d64adc3a79e419062432cfa8d1cbc437676a3fbd has been incorporated to mesa by 10.5.4 and I can report that I still have the same issue. I also built mesa from git in Arch Linux using the AUR mesa-git and lib32-mesa-git tarballs, installed, and tried Dota with no success.