Matrox has a closed driver for the P-series cards (P650, P750, Parhelia) at: http://www.matrox.com/mga/support/drivers/latest/home.cfm (though you do have to register to download it, still) To the best of my knowledge, no one has approached Matrox about opening this driver.
Sorry about the phenomenal bug spam, guys. Adding xorg-team@ to the QA contact so bugs don't get lost in future.
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