Testing a Matrox G400 card here I verified that it was not updating the drawable state after the window was moved causing some interesting effects (the window moves, but no the contents).
Adding a DRI_VALIDATE_DRAWABLE_INFO() call in mgaGetLock() fixed the problem here. Patch following.
Created attachment 9392 [details] [review]
Check the drawable state when getting the lock
I checked in your fix. Thanks.
Could anyone confirm that this is the same bug as #9210? I can't test it right now.
I guess it is the same, but it would be nice if you could test before closing that one.
*** Bug 9210 has been marked as a duplicate of this bug. ***